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| Publications of April S. Brown :chronological alphabetical combined listing:
%% Papers Published
@booklet{Wu09,
Author = {P. C. Wu and M. Losurdo and T. H. Kim and M. Giangregorio and G. Bruno and H. O. Everitt and A. S.
Brown},
Title = {Plasmonic Gallium Nanoparticles on Polar Semiconductors:
Interplay between Nanoparticle Wetting, Localized Surface
Plasmon Dynamics, and Interface Charge},
Journal = {Langmuir},
Volume = {25},
Number = {2},
Pages = {924 -- 930},
Year = {2009},
Month = {January},
ISSN = {0743-7463},
Abstract = {Ga nanoparticles supported on large band gap semiconductors
like SiC, GaN, and ZnO are interesting for plasmon-enhanced
UV-emitting solid-state devices. We investigate the
influence of the polarity of the SiC, GaN, and ZnO wurtzite
semiconductors on the wetting of Ga nanoparticles and on the
resulting surface plasmon resonance (SPR) by exploiting real
time plasmonic ellipsometry. The interface potential between
polar semiconductors (SiC, GaN, and ZnO) and plasmonic
nanoparticles (gallium) is shown to influence nanoparticle
formation dynamics, geometry, and consequently the SPR
wavelength. We invoke the Lippman electrowetting framework
to elucidate the mechanisms controlling nanoparticle
dynamics and experimentally demonstrate that the charge
transfer at the Ga nanoparticle/polar semiconductor
interface is an intrinsic method for tailoring the
nanoparticle plasmon resonance. Therefore, the present data
demonstrate that for supported nanoparticles, surface and
interface piezoelectric charge of polar semiconductors also
affects SPR along with the well-known effect of the media
refractive index.},
Key = {Wu09}
}
@booklet{Garcia08,
Author = {M. A. Garcia and M. Losurdo and S. D. Wolter and W. V.
Lampert and J. Bonaventura and G. Bruno and C. Yi and A. S.
Brown},
Title = {Comparison of Functionalized III-V Semiconductor Response
for Nitric Oxide},
Journal = {Sensor Letters},
Volume = {6},
Number = {4},
Pages = {627 -- 634},
Year = {2008},
Month = {August},
ISSN = {1546-198X},
Abstract = {Several III-V materials systems, consisting of InAs, InP,
and GaN, were chemically functionalized, characterized, and
evaluated for Nitric Oxide (NO) sensor research. The hemin
porphyrin has been a particularly successful NO detection
functional group for carbon-based material systems for
sensors. The unique sensing modalities inherent in an InAs
surface accumulation layer and the AlGaN/GaN surface
polarization charge coupling motivated enhanced chemical
sensor exploration. NO's diverse roles in defense,
biological, and environmental fields create interest in the
development of responsive and selective solid state sensors.
In a controlled gaseous environment, functionalized and
pre-functionalized III-V semiconductor materials were probed
for changes in resistivity during exposure to varying
concentrations of NO, NO2, O-2 and Ar. X-ray photoelectron
spectroscopy was used to characterize sample
functionalization and analyte influences on the valence band
maxima in order to better understand the charge transduction
mechanisms. The results of the trials were compared and
analyzed for optimization and materials recommendations.},
Key = {Garcia08}
}
@booklet{Losurdo07,
Author = {M. Losurdo and M. M. Giangregorio and G. Bruno and T. H. Kim and S. Choi and A. S. Brown and G. Pettinari and M. Capizzi and A. Polimeni},
Title = {Behavior of hydrogen in InN investigated in real time
exploiting spectroscopic ellipsometry},
Journal = {Applied Physics Letters},
Volume = {91},
Number = {8},
Year = {2007},
Month = {August},
ISSN = {0003-6951},
Abstract = {The interaction of hydrogen with InN epitaxial films has
been investigated by exposing InN to a remote hydrogen
plasma and monitoring changes in the InN optical properties
in real time via spectroscopic ellipsometry. Atomic hydrogen
reacts swith InN causing nitrogen depletion with formation
of indium clusters at the sample surface. After terminating
the hydrogenation process, the hydrogen remains stable in
the InN host lattice at T $<$ 200 degrees C, while at higher
temperatures it partially desorbs as NHx and InHx
(x=1-3).},
Key = {Losurdo07}
}
@booklet{Mckay07,
Author = {K. S. Mckay and F. P. Lu and J. Kim and C. H. Yi and A. S.
Brown and A. R. Hawkins},
Title = {Band discontinuity measurements of the wafer bonded
InGaAs/Si heterojunction},
Journal = {Applied Physics Letters},
Volume = {90},
Number = {22},
Year = {2007},
Month = {May},
ISSN = {0003-6951},
Abstract = {p-type InGaAs/Si heterojunctions were fabricated through a
wafer fusion bonding process. The relative band alignment
between the two materials at the heterointerface was
determined using current-voltage (I-V) measurements and
applying thermionic emission-diffusion theory. The valence
and conduction band discontinuities for the InGaAs/Si
interface were determined to be 0.48 and -0.1 eV,
respectively, indicating a type-II band alignment. (C) 2007
American Institute of Physics.},
Key = {Mckay07}
}
@booklet{Uhlrich07,
Author = {J. Uhlrich and M. Garcia and S. Wolter and A. S. Brown and T. F. Kuech},
Title = {Interfacial chemistry and energy band line-up of pentacene
with the GaN (0001) surface},
Journal = {Journal Of Crystal Growth},
Volume = {300},
Number = {1},
Pages = {204 -- 211},
Year = {2007},
Month = {March},
ISSN = {0022-0248},
Abstract = {The chemical nature of the GaN surface combined with the
bulk and surface electronic structure opens new potential
application areas for this material. The nature of specific
organic-GaN was developed for two cases in which the surface
electronic structure of such interfaces was developed and
utilized. The band alignment between n-GaN and pentacene was
determined for surfaces prepared through reaction with HCl.
The energy band offset was estimated through combined X-ray
photoelectron spectroscopy and ultraviolet photoemission
measurements. XPS measurements indicated that there was no
interfacial chemical reaction. The measured valence band
offset between the n-GaN and the vapor-deposited pentacene
was estimated to be greater than 2 eV providing a favorable
band-offset for hole-injection from the GaN layer into
pentacene. The surface of a AlGaN/GaN heterojunction field
effect transistor (HFET) structures was also functionalized
by an adsorbed hemin layer and was shown to be sensitive to
the presence of reactive species such as NO. The HFET
structure provides enhanced sensitivity to changes in the
surface electric field, altered through the adsorption of
chemically active species either directly on the surface or
through the interactions with surface functionalization. (c)
2006 Elsevier B.V. All rights reserved.},
Key = {Uhlrich07}
}
@booklet{Wu07a,
Author = {P. C. Wu and T. H. Kim and A. S. Brown and M. Losurdo and G.
Bruno and H. O. Everitt},
Title = {Real-time plasmon resonance tuning of liquid Ga
nanoparticles by in situ spectroscopic ellipsometry},
Journal = {Applied Physics Letters},
Volume = {90},
Number = {10},
Year = {2007},
Month = {March},
ISSN = {0003-6951},
Abstract = {Liquid Ga nanoparticles have been deposited on sapphire
substrates at room temperature. The optical evolution of Ga
nanoparticle surface plasmon resonance during deposition has
been characterized by in situ real-time spectroscopic
ellipsometry to control and tune the plasmon resonance
photon energy. The existence of both longitudinal and
transverse modes for spheroidal Ga nanoparticles supported
on a sapphire substrate is demonstrated and the dependence
of the longitudinal and transverse plasmon energies on
particle size is discussed. Stability of the Ga surface
plasmon resonance to air exposure and high temperature is
also demonstrated. (c) 2007 American Institute of
Physics.},
Key = {Wu07a}
}
@article{070910462413,
Author = {Uhlrich, J. and Garcia, M. and Wolter, S. and Brown, A.S. and Kuech, T.F.},
Title = {Interfacial chemistry and energy band line-up of pentacene
with the GaN (0 0 0 1) surface},
Journal = {Journal of Crystal Growth},
Volume = {300},
Number = {1},
Pages = {204 - 211},
Year = {2007},
url = {http://dx.doi.org/10.1016/j.jcrysgro.2006.11.035},
Keywords = {Band structure;Gallium nitride;Interfaces
(materials);Junction gate field effect transistors;Metallorganic
vapor phase epitaxy;Reaction kinetics;Surface chemistry;X
ray photoelectron spectroscopy;},
Abstract = {The chemical nature of the GaN surface combined with the
bulk and surface electronic structure opens new potential
application areas for this material. The nature of specific
organic-GaN was developed for two cases in which the surface
electronic structure of such interfaces was developed and
utilized. The band alignment between n-GaN and pentacene was
determined for surfaces prepared through reaction with HCl.
The energy band offset was estimated through combined X-ray
photoelectron spectroscopy and ultraviolet photoemission
measurements. XPS measurements indicated that there was no
interfacial chemical reaction. The measured valence band
offset between the n-GaN and the vapor-deposited pentacene
was estimated to be greater than 2 eV providing a favorable
band-offset for hole-injection from the GaN layer into
pentacene. The surface of a AlGaN/GaN heterojunction field
effect transistor (HFET) structures was also functionalized
by an adsorbed hemin layer and was shown to be sensitive to
the presence of reactive species such as NO. The HFET
structure provides enhanced sensitivity to changes in the
surface electric field, altered through the adsorption of
chemically active species either directly on the surface or
through the interactions with surface functionalization.
© 2006 Elsevier B.V. All rights reserved.},
Key = {070910462413}
}
@article{071110490609,
Author = {Wu, Pae C and Kim, Tong-Ho and Brown, April S. and Losurdo,
Maria and Bruno, Giovanni and Everitt, Henry
O.},
Title = {Real-time plasmon resonance tuning of liquid Ga
nanoparticles by in situ spectroscopic ellipsometry},
Journal = {Applied Physics Letters},
Volume = {90},
Number = {10},
Pages = {103119 -},
Year = {2007},
url = {http://dx.doi.org/10.1063/1.2712508},
Keywords = {Gallium compounds;Particle size;Real time
systems;Sapphire;Spectroscopic ellipsometry;Surface plasmon
resonance;},
Abstract = {Liquid Ga nanoparticles have been deposited on sapphire
substrates at room temperature. The optical evolution of Ga
nanoparticle surface plasmon resonance during deposition has
been characterized by in situ real-time spectroscopic
ellipsometry to control and tune the plasmon resonance
photon energy. The existence of both longitudinal and
transverse modes for spheroidal Ga nanoparticles supported
on a sapphire substrate is demonstrated and the dependence
of the longitudinal and transverse plasmon energies on
particle size is discussed. Stability of the Ga surface
plasmon resonance to air exposure and high temperature is
also demonstrated. © 2007 American Institute of
Physics.},
Key = {071110490609}
}
@booklet{Yoon07,
Author = {I. Yoon and C. Yi and T. Kirn and A. S. Brown and A.
Seabaugh},
Title = {Effect of surface pretreatment and substrate orientation on
the characteristics of InAs quantum dots on Si and SiO2
substrates},
Journal = {Journal Of Vacuum Science \& Technology B},
Volume = {25},
Number = {3},
Pages = {945 -- 947},
Year = {2007},
ISSN = {1071-1023},
Abstract = {The surface m orphology of InAs quantum dots (QDs) on
undoped Si (100) shows a strong dependency on surface
pretreatments, with as much as 30\% difference in island
density with different size distributions. Lowering the
V/III fluxes ratio (5 8: 1 to 10: 1) effectively suppresses
the average height (47\%) and increases density (75\%) of
QDs. While changing the growth temperature (220-300 degrees
C) increased the average height by 62\% on chemically etched
Si surfaces, nucleation on the SiO2 surface was less
sensitive to surface preparation. The authors alsd observe
that the specific substrate orientation and annealing at 500
degrees C do not significantly impact the morphology of QDs.
(c) 2007 American Vacuum Society.},
Key = {Yoon07}
}
@booklet{Wu07,
Author = {P. C. Wu and M. Losurdo and T. H. Kim and O. Choi and G.
Bruno and A. S. Brown},
Title = {In situ spectroscopic ellipsometry to monitor surface
plasmon resonant group-III metals deposited by molecular
beam epitaxy},
Journal = {Journal Of Vacuum Science \& Technology B},
Volume = {25},
Number = {3},
Pages = {1019 -- 1023},
Year = {2007},
ISSN = {1071-1023},
Abstract = {The evolution of the surface plasmon resonance of Al, Ga,
and In deposited by molecular beam epitaxy on GaN surfaces
was monitored in real-time using spectroscopic ellipsometry.
The correlation between the metal plasmon resonance modes,
the particle size, and the growth mode is addressed. Gaand
In deposited on GaN substrates form nanoparticles while the
Al is shown to form a nearly coalesced thin film. The
plasmon resonance of the Ga and In nanoparticles redshift
with increasing average particle size while the
pseudodielectric function of Al approaches that of a Drude
metal. (c) 2007 American Vacuum Society.},
Key = {Wu07}
}
@booklet{Bruno06,
Author = {G. Bruno and M. Losurdo and M. M. Giangregorio and P.
Capezzuto and A. S. Brown and T. H. Kim and S.
Choi},
Title = {Real time ellipsometry for monitoring plasma-assisted
epitaxial growth of GaN},
Journal = {Applied Surface Science},
Volume = {253},
Number = {1},
Pages = {219 -- 223},
Year = {2006},
Month = {October},
ISSN = {0169-4332},
Abstract = {GaN is grown on Si-face 4H-SiC(001) substrates using remote
plasma-assisted methods including metalorganic chemical
vapour deposition (RP-MOCVD) and molecular beam epitaxy
(MBE). Real time spectroscopic ellipsometry is used for
monitoring all the steps of substrate pre-treatments and the
heteroepitaxial growth of GaN on SiC. Our characterization
emphasis is on understanding the nucleation mechanism and
the GaN growth mode, which depend on the SiC surface
preparation. (c) 2006 Elsevier B.V. All rights
reserved.},
Key = {Bruno06}
}
@booklet{Morse06,
Author = {M. Morse and P. Wu and S. Choi and T. H. Kim and A. S. Brown and M. Losurdo and G. Bruno},
Title = {Structural and optical characterization of GaN
heteroepitaxial films on SiC substrates},
Journal = {Applied Surface Science},
Volume = {253},
Number = {1},
Pages = {232 -- 235},
Year = {2006},
Month = {October},
ISSN = {0169-4332},
Abstract = {We have estimated the threading dislocation density and type
via X-ray diffraction and Williamson-Hall analysis to elicit
qualitative information directly related to the electrical
and optical quality of GaN epitaxial layers grown by PAMBE
on 4H- and 6H-SiC substrates. The substrate surface
preparation and buffer choice, specifically: Ga flashing for
SiC oxide removal, controlled nitridation of SiC, and use of
AlN buffer layers all impact the resultant screw dislocation
density, but do not significantly influence the edge
dislocation density. We show that modification of the
substrate surface strongly affects the screw dislocation
density, presumably due to impact on nucleation during the
initial stages of heteroepitaxy. (c) 2006 Published by
Elsevier B.V.},
Key = {Morse06}
}
@booklet{Yi06,
Author = {C. H. Yi and T. H. Kim and A. S. Brown},
Title = {InAs-based p-n homojunction diodes: Doping effects and
impact of doping on device parameters},
Journal = {Journal Of Electronic Materials},
Volume = {35},
Number = {9},
Pages = {1712 -- 1714},
Year = {2006},
Month = {September},
ISSN = {0361-5235},
Abstract = {InAs heterojunction bipolar transistors (HBTs) are promising
candidates for low power and high frequency (THz) device
applications due to their small bandgap, high electron
mobility, and high saturation drift velocity. However,
doping limits such as the trade-off between desired low
intentional n-type concentrations and unintentional doping,
and the realization of high p-type concentrations, must
still be considered in device design and synthesis. In order
to observe the impact of intentional and unintentional
n-type doping on diode electrical properties, InAs-based
homojunction diodes have been grown on InAs substrates by
solid-source molecular beam epitaxy (SSMBE) and were
subsequently fabricated and characterized.},
Key = {Yi06}
}
@booklet{Triplett06,
Author = {G. E. Triplett and A. S. Brown and G. S.
May},
Title = {Strain monitoring in InAs-AlxGa1-xAsySb1-y structures grown
by molecular beam epitaxy},
Journal = {Applied Physics Letters},
Volume = {89},
Number = {3},
Pages = {345 -- 349},
Year = {2006},
Month = {July},
ISSN = {0003-6951},
Abstract = {A study of strained InAs-AlxGa1-xAsySb1-y quantum well
structures produced by molecular beam epitaxy is presented.
The ability to manipulate quantum well strain by way of the
AlxGa1-xAsySb1-y buffer is examined using statistical
experimental design. Results show that anion composition in
the buffer (with a target lattice constant, a=6.12 angstrom)
varies by as much as 3\% in the 450-500 degrees C growth
temperature range. The data reveal interrelationships
between strain, structural characteristics, and
conductivity. Results demonstrate that these relationships
exist and can be modeled empirically and exploited for the
design of near-infrared optoelectronic devices. (c) 2006
American Institute of Physics.},
Key = {Triplett06}
}
@booklet{Losurdo06,
Author = {M. Losurdo and P. Capezzuto and G. Bruno and A. S. Brown and T. Brown and G. May},
Title = {Fundamental reactions controlling anion exchange during
mixed anion heterojunction formation: Chemistry of As-for-Sb
and Sb-for-As exchange reactions},
Journal = {Journal Of Applied Physics},
Volume = {100},
Number = {1},
Year = {2006},
Month = {July},
ISSN = {0021-8979},
Abstract = {As-for-Sb and Sb-for-As anion exchange reactions have been
investigated by the exposure of GaSb surfaces to As-2 and
As-4 species and by the exposure of GaAs to Sb-2,
respectively. The effect of surface temperature, anion soak
time, and anion species (either As-2 or As-4) on the
chemistry governing the anion exchange reactions during
GaAsySb1-y/GaSb and GaSbyAs1-y/GaAs heterostructure
formation by molecular beam epitaxy is examined. It is found
that when GaSb surfaces are exposed to arsenic, the anion
exchange reaction competes with the formation of
isoelectronic compounds, AsSby, which form clusters
precipitating in the GaAsySb1-y/GaSb heterostructures. The
relative amount of GaAs and AsSby depends on the surface
temperature, the As soak time, and on the As species, i.e.,
As-2 or As-4. We observe specific process conditions that
minimize AsSby formation, yielding more abrupt
heterojunction interfaces. In the case of the Sb-2/GaAs
system, the Sb-for-As anion exchange does not occur to a
significant degree, but surface segregation of antimony is
found. A chemical model for the As-for-Sb anion exchange
reaction is proposed. (c) 2006 American Institute of
Physics.},
Key = {Losurdo06}
}
@booklet{Kim06,
Author = {T. H. Kim and S. Choi and A. S. Brown and M. Losurdo and G.
Bruno},
Title = {Impact of 4H- and 6H-SiC(0001) nitridation on Ga wetting
layer development and GaN growth by molecular beam
epitaxy},
Journal = {Applied Physics Letters},
Volume = {89},
Number = {2},
Year = {2006},
Month = {July},
ISSN = {0003-6951},
Abstract = {GaN epitaxial layers have been grown by plasma-assisted
molecular beam epitaxy on Si-face 4H- and 6H-SiC(0001)(Si)
substrates. The impact of the SiC surface preparation and
oxide removal achieved via a Ga flash-off process followed
by nitridation on the structure and properties of GaN
epitaxial layers is articulated. A correlation among the SiC
surface nitridation conditions, the Ga wetting layer
development, the nucleation layer, and GaN crystalline
properties is revealed. (c) 2006 American Institute of
Physics.},
Key = {Kim06}
}
@booklet{Brown06,
Author = {A. S. Brown and M. Losurdo and P. Capezzuto and G. Bruno and T. Brown and G. May},
Title = {Fundamental reactions controlling anion exchange during
mixed anion heterojunction formation: Chemistry and kinetics
of P-for-As exchange reaction},
Journal = {Journal Of Applied Physics},
Volume = {99},
Number = {9},
Year = {2006},
Month = {May},
ISSN = {0021-8979},
Abstract = {The fundamental chemical and kinetic surface processes
governing the P-for-As exchange reaction during epitaxial
layer synthesis are investigated. Exposure of a GaAs surface
to phosphorus molecular beams (P-2) is carried out to create
superlattice structures realized by surface reactions. The
impact of the GaAs surface reconstruction, the P-soak time,
and the surface temperature on the extent of intermixing and
on the mechanism governing the anion exchange has been
studied using x-ray diffraction, spectroscopic ellipsometry,
x-ray photoelectron spectroscopy, and atomic force
microscopy. It is found that As-rich GaAs surface
reconstructions inhibit P-for-As exchange. The extent of the
anion exchange increases with temperature. Furthermore, the
P-for-As exchange is not controlled by P diffusion into the
GaAs. We propose a chemical model that includes P
chemisorption and indiffusion, and the competition between
P-for-As anion exchange and the formation of AsP
isoelectronic compounds. (C) 2006 American Institute of
Physics.},
Key = {Brown06}
}
@booklet{Triplett06a,
Author = {G. E. Triplett and A. S. Brown and G. S.
May},
Title = {Interrelationships in the electronic and structural
characteristics of strained InAs quantum well
structures},
Journal = {Journal Of Crystal Growth},
Volume = {286},
Number = {2},
Pages = {345 -- 349},
Year = {2006},
Month = {January},
ISSN = {0022-0248},
Abstract = {Indium-arsenide (InAs)-based devices are promising for next
generation electronic and optoelectronic applications.
Improving these devices requires greater control of the InAs
quantum well properties, which in part, are related to the
strain induced from the substrate material, buffer layer
thickness, barrier composition, doping, and the
heterointerface. This report focuses on the latter and
includes X-ray diffraction and Hall results from a
statistical experimental design (SED), which focused on the
growth sequence at the heterointerface and growth throughout
the channel, and illuminates correlations between structural
variations and the electronic properties in strained InAs
quantum well structures produced by molecular beam epitaxy
(MBE). This data suggest that as more antimony from the
sublayer is incorporated in the InAs layer, a product of
anion exchange between antimony surface atoms and ensuing
arsenic flux atoms, the strain states vary along with InAs
channel mobility. (c) 2005 Elsevier B.V. All rights
reserved.},
Key = {Triplett06a}
}
@article{063110037506,
Author = {Brown, April S. and Kim, Tong-Ho and Choi, Soojeong and Wu,
Pae and Morse, Michael and Losurdo, Maria and Giangregorio,
Maria M. and Bruno, Giovanni and Moto, Akihiro},
Title = {Growth of InN on 6H-SiC by plasma assisted molecular beam
epitaxy},
Journal = {Physica Status Solidi C: Current Topics in Solid State
Physics},
Volume = {3},
Pages = {1531 - 1535},
Address = {Bremen, Germany},
Year = {2006},
url = {http://dx.doi.org/10.1002/pssc.200565150},
Keywords = {Semiconducting silicon compounds;Molecular beam
epitaxy;Epitaxial growth;Annealing;Ellipsometry;Electric
properties;Optical properties;},
Abstract = {We have investigated the growth of InN films by plasma
assisted molecular beam epitaxy on the Si-face of
6H-SiC(0001). Growth is performed under In-rich conditions
using a two-step process consisting of the deposition of a
thin, low-temperature 350°C InN buffer layer, followed
by the subsequent deposition of the InN epitaxial layer at
450°C. The effect of buffer annealing is investigated.
The structural and optical evolution of the growing layer
has been monitored in real time using RHEED and
spectroscopic ellipsometry. Structural, morphological,
electrical and optic properties are discussed. © 2006
WILEY-VCH Verlag GmbH and Co. KGaA.},
Key = {063110037506}
}
@article{06229911078,
Author = {Brown, April S. and Losurdo, Maria and Capezzuto, Pio and Bruno, Giovanni and Brown, Terence and May,
Gary},
Title = {Fundamental reactions controlling anion exchange during
mixed anion heterojunction formation: Chemistry and kinetics
of P-for-As exchange reaction},
Journal = {Journal of Applied Physics},
Volume = {99},
Number = {9},
Pages = {093510 -},
Year = {2006},
url = {http://dx.doi.org/10.1063/1.2194126},
Keywords = {Reaction kinetics;Surface properties;Epitaxial
growth;Superlattices;Semiconducting gallium compounds;X ray
diffraction analysis;Ellipsometry;X ray photoelectron
spectroscopy;Ion exchange;Chemisorption;},
Abstract = {The fundamental chemical and kinetic surface processes
governing the P-for-As exchange reaction during epitaxial
layer synthesis are investigated. Exposure of a GaAs surface
to phosphorus molecular beams (P2) is carried out to create
superlattice structures realized by surface reactions. The
impact of the GaAs surface reconstruction, the P-soak time,
and the surface temperature on the extent of intermixing and
on the mechanism governing the anion exchange has been
studied using x-ray diffraction, spectroscopic ellipsometry,
x-ray photoelectron spectroscopy, and atomic force
microscopy. It is found that As-rich GaAs surface
reconstructions inhibit P-for-As exchange. The extent of the
anion exchange increases with temperature. Furthermore, the
P-for-As exchange is not controlled by P diffusion into the
GaAs. We propose a chemical model that includes P
chemisorption and indiffusion, and the competition between
P-for-As anion exchange and the formation of AsP
isoelectronic compounds. © 2006 American Institute of
Physics.},
Key = {06229911078}
}
@article{06019623333,
Author = {Triplett, Gregory Edward and Brown, April S. and May, Gary
S.},
Title = {Interrelationships in the electronic and structural
characteristics of strained InAs quantum well
structures},
Journal = {Journal of Crystal Growth},
Volume = {286},
Number = {2},
Pages = {345 - 349},
Year = {2006},
url = {http://dx.doi.org/10.1016/j.jcrysgro.2005.10.098},
Keywords = {Semiconducting indium compounds;Optoelectronic
devices;Strain;Semiconductor doping;Hall effect;X ray
diffraction;Ion exchange;Molecular beam epitaxy;},
Abstract = {Indium-arsenide (InAs)-based devices are promising for next
generation electronic and optoelectronic applications.
Improving these devices requires greater control of the InAs
quantum well properties, which in part, are related to the
strain induced from the substrate material, buffer layer
thickness, barrier composition, doping, and the
heterointerface. This report focuses on the latter and
includes X-ray diffraction and Hall results from a
statistical experimental design (SED), which focused on the
growth sequence at the heterointerface and growth throughout
the channel, and illuminates correlations between structural
variations and the electronic properties in strained InAs
quantum well structures produced by molecular beam epitaxy
(MBE). This data suggest that as more antimony from the
sublayer is incorporated in the InAs layer, a product of
anion exchange between antimony surface atoms and ensuing
arsenic flux atoms, the strain states vary along with InAs
channel mobility. © 2005 Elsevier B.V. All rights
reserved.},
Key = {06019623333}
}
@article{063010023324,
Author = {Kim, Tong-Ho and Choi, Soojeong and Brown, April S. and Losurdo, Maria and Bruno, Giovanni},
Title = {Impact of 4H- And 6H-SiC(0001) nitridation on Ga wetting
layer development and GaN growth by molecular beam
epitaxy},
Journal = {Applied Physics Letters},
Volume = {89},
Number = {2},
Pages = {021916 -},
Year = {2006},
url = {http://dx.doi.org/10.1063/1.2220007},
Keywords = {Gallium nitride;Epitaxial growth;Oxides;Nucleation;Molecular
beam epitaxy;},
Abstract = {GaN epitaxial layers have been grown by plasma-assisted
molecular beam epitaxy on Si-face 4H-and
6H-SiC(0001)<sub>Si</sub> substrates. The impact of the SiC
surface preparation and oxide removal achieved via a Ga
flash-off process followed by nitridation on the structure
and properties of GaN epitaxial layers is articulated. A
correlation among the SiC surface nitridation conditions,
the Ga wetting layer development, the nucleation layer, and
GaN crystalline properties is revealed. © 2006 American
Institute of Physics.},
Key = {063010023324}
}
@article{064510222023,
Author = {Bruno, Giovanni and Losurdo, Maria and Giangregorio, Maria
M. and Capezzuto, Pio and Brown, April S. and Kim, Tong-Ho and Choi, Soojeong},
Title = {Real time ellipsometry for monitoring plasma-assisted
epitaxial growth of GaN},
Journal = {Applied Surface Science},
Volume = {253},
Number = {1 SPEC ISS},
Pages = {219 - 223},
Year = {2006},
url = {http://dx.doi.org/10.1016/j.apsusc.2006.05.129},
Keywords = {Ellipsometry;Epitaxial growth;Silicon carbide;Plasma
applications;Metallorganic chemical vapor
deposition;Nucleation;},
Abstract = {GaN is grown on Si-face 4H-SiC(0 0 0 1) substrates using
remote plasma-assisted methods including metalorganic
chemical vapour deposition (RP-MOCVD) and molecular beam
epitaxy (MBE). Real time spectroscopic ellipsometry is used
for monitoring all the steps of substrate pre-treatments and
the heteroepitaxial growth of GaN on SiC. Our
characterization emphasis is on understanding the nucleation
mechanism and the GaN growth mode, which depend on the SiC
surface preparation. © 2006 Elsevier B.V. All rights
reserved.},
Key = {064510222023}
}
@article{064510222017,
Author = {Morse, M. and Wu, P. and Choi, S. and Kim, T.H. and Brown,
A.S. and Losurdo, M. and Bruno, G.},
Title = {Structural and optical characterization of GaN
heteroepitaxial films on SiC substrates},
Journal = {Applied Surface Science},
Volume = {253},
Number = {1 SPEC ISS},
Pages = {232 - 235},
Year = {2006},
url = {http://dx.doi.org/10.1016/j.apsusc.2006.05.097},
Keywords = {Gallium nitride;Silicon carbide;Optical properties;X ray
diffraction;Dislocations (crystals);Nucleation;},
Abstract = {We have estimated the threading dislocation density and type
via X-ray diffraction and Williamson-Hall analysis to elicit
qualitative information directly related to the electrical
and optical quality of GaN epitaxial layers grown by PAMBE
on 4H- and 6H-SiC substrates. The substrate surface
preparation and buffer choice, specifically: Ga flashing for
SiC oxide removal, controlled nitridation of SiC, and use of
AlN buffer layers all impact the resultant screw dislocation
density, but do not significantly influence the edge
dislocation density. We show that modification of the
substrate surface strongly affects the screw dislocation
density, presumably due to impact on nucleation during the
initial stages of heteroepitaxy. © 2006.},
Key = {064510222017}
}
@article{063010033806,
Author = {Triplett, Gregory E. and Brown, April S. and May, Gary
S.},
Title = {Strain monitoring in InAs-AlxGa1-xAS
ySb1-y structures grown by molecular
beam epitaxy},
Journal = {Applied Physics Letters},
Volume = {89},
Number = {3},
Pages = {032106 -},
Year = {2006},
url = {http://dx.doi.org/10.1063/1.2226998},
Keywords = {Semiconductor quantum wells;Molecular beam
epitaxy;Statistical methods;Negative ions;Strain;Optoelectronic
devices;},
Abstract = {A study of strained InAs-Al<sub>x</sub>Ga<sub>1-x</sub>As
<sub>y</sub>Sb<sub>1-y</sub> quantum well structures
produced by molecular beam epitaxy is presented. The ability
to manipulate quantum well strain by way of the
Al<sub>x</sub>Ga<sub>1-x</sub>As<sub>y</sub>Sb<sub>1-y</sub>
buffer is examined using statistical experimental design.
Results show that anion composition in the buffer (with a
target lattice constant, a=6.12 A) varies by as much as 3%
in the 450-500°C growth temperature range. The data
reveal interrelationships between strain, structural
characteristics, and conductivity. Results demonstrate that
these relationships exist and can be modeled empirically and
exploited for the design of near-infrared optoelectronic
devices. © 2006 American Institute of
Physics.},
Key = {063010033806}
}
@article{064110158746,
Author = {Yi, Changhyun and Kim, Tong-Ho and Brown, April
S.},
Title = {InAs-based p-n homojunction diodes: Doping effects and
impact of doping on device parameters},
Journal = {Journal of Electronic Materials},
Volume = {35},
Number = {9},
Pages = {1712 - 1714},
Year = {2006},
Keywords = {Semiconducting indium compounds;Semiconductor
doping;Heterojunction bipolar transistors;Electron
mobility;Product design;Electric properties;Molecular beam
epitaxy;},
Abstract = {InAs heterojunction bipolar transistors (HBTs) are promising
candidates for low power and high frequency (THz) device
applications due to their small bandgap, high electron
mobility, and high saturation drift velocity. However,
doping limits such as the trade-off between desired low
intentional n-type concentrations and unintentional doping,
and the realization of high p-type concentrations, must
still be considered in device design and synthesis. In order
to observe the impact of intentional and unintentional
n-type doping on diode electrical properties, InAs-based
homojunction diodes have been grown on InAs substrates by
solid-source molecular beam epitaxy (SSMBE) and were
subsequently fabricated and characterized.},
Key = {064110158746}
}
@article{05209101122,
Author = {Losurdo, Maria and Giangregorio, Maria M. and Capezzuto, Pio and Bruno, Giovanni and Brown, April S. and Kim, Tong-Ho and Yi, Changhyun},
Title = {Modification of 4H-SiC and 6H-SiC(0001)Si
surfaces through the interaction with atomic hydrogen and
nitrogen},
Journal = {Journal of Electronic Materials},
Volume = {34},
Number = {4},
Pages = {457 - 465},
Year = {2005},
Keywords = {Surface chemistry;Hydrogen;Nitrogen;Hydrogenation;Plasma
applications;Reaction kinetics;X ray photoelectron
spectroscopy;Atomic force microscopy;Thermal
effects;Passivation;Crystal orientation;Energy gap;Epitaxial
growth;Geometry;},
Abstract = {The interaction of 4H-SiC(0001)<sub>Si</sub> and
6H-SiC(0001)<sub>Si</sub> surfaces with atomic hydrogen and
atomic nitrogen produced by remote radio-frequency plasmas
is investigated. The kinetics of the surface modifications
is monitored in real time using ellipsometry, while chemical
modifications of the surface are characterized using x-ray
photoelectron spectroscopy (XPS). Film morphological
properties are assessed with atomic force microscopy (AFM).
A two-stage sub-strate preparation procedure is described
that effectively removes oxygen from the SiC surface at low
(200°C) temperature. In the first step, the SiC surface
is etched with an HCl/HF acid solution as an alternative to
the conventional HF(1%)-H<sub>2</sub>O solution. The HCl/HF
etch provides effective hydrogen passivation of the SiC
surface. In the second step, the SiC surface is exposed to
atomic hydrogen that selectively interacts with residual
oxygen. In addition, the temperature dependence of the
nitridation of SiC surfaces has also been investigated. It
is found that interaction of SiC surfaces with atomic
hydrogen at 200°C provides clean, smooth, and terraced
surfaces suitable for epitaxial growth. In contrast, SiC
surface exposure at high temperature (750°C) to atomic
hydrogen and nitrogen results in very rough and disordered
Si-rich surfaces. Finally, we find that the 4H-SiC surface
is more reactive than the 6H-SiC surface to both species
studied, independent of temperature. Surface geometry and
electronic factors responsible for the observed reactivities
are discussed.},
Key = {05209101122}
}
@article{05479486792,
Author = {Brown, A.S. and Losurdo, M. and Kim, T.H. and Giangregorio,
M.M. and Choi, S. and Morse, M. and Wu, P. and Capezzuto, P. and Bruno, G.},
Title = {The impact of SiC substrate treatment on the heteroepitaxial
growth of GaN by plasma assisted MBE},
Journal = {Crystal Research and Technology},
Volume = {40},
Number = {10-11},
Pages = {997 - 1002},
Year = {2005},
url = {http://dx.doi.org/10.1002/crat.200410475},
Keywords = {Epitaxial growth;Semiconducting gallium arsenide;Nitrides;Nucleation;X
ray photoelectron spectroscopy;Atomic force
microscopy;Spectroscopic analysis;Surface
treatment;},
Abstract = {We report on the impact of the preparation of the Si-face
4H-SiC(0001) <sub>Si</sub> substrate using a Ga flash-off
process on the epitaxial growth of GaN by plasma-assisted
molecular beam epitaxy. The nucleation, as well as the
resultant structural and morphological properties of GaN
grown directly on 4H-SiC(0001)<sub>Si</sub> are strongly
influenced by the chemical and morphological modifications
of the SiC surface induced by the Ga flash-off process.
Herein we describe the impact of the specific concentration
of Ga incident on the surface (quantified in terms of
monolayer (ML) coverage): of 0.5 ML, 1ML and 2ML. The
residual oxygen at the SiC surface, unintentional SiC
nitridation and the formation of cubic GaN grains during the
initial nucleation stage, are all reduced when a 2 ML Ga
flash is used. All of the above factors result in structural
improvement of the GaN epitaxial layers. The correlation
between the SiC surface modification, the initial nucleation
stage, and the GaN epitaxial layer structural quality has
been articulated using x-ray photoelectron spectroscopy,
x-ray diffraction, atomic force microscopy and spectroscopic
ellipsometry data. © 2005 WILEY-VCH Verlag GmbH and Co.
KGaA, Weinheim.},
Key = {05479486792}
}
@article{05319271476,
Author = {Collins, Leslie M. and Huettel, Lisa G. and Brown, April S. and Ybarra, Gary A. and Holmes, Joseph S. and Board, John A. and Cummer, Steven A. and Gustafson, Michael R. and Kim,
Jungsang and Massoud, Hisham Z.},
Title = {Theme-based redesign of the duke university ECE curriculum:
The first steps},
Journal = {ASEE Annual Conference and Exposition, Conference
Proceedings},
Pages = {14313 - 14326},
Address = {Portland, OR, United States},
Year = {2005},
Keywords = {Students;Curricula;Planning;Data processing;Electronic
equipment;Benchmarking;},
Abstract = {Undergraduates in Electrical and Computer Engineering (ECE)
at Duke University have benefited from the combination of
curricular flexibility and rigorous coursework. The current
curriculum is further limited in that the core courses do
not offer a vertically integrated thematic introduction to
ECE as a discipline nor are they reflective of the broader
scope of ECE field of study. The course has streamlined
structure, which is consistent with an educational theme.
Results from Educational BEnchmark Inc. (EBI) survey of
students confirmed that they too perceive the oppurtinities
for improvement in curriculum.},
Key = {05319271476}
}
@article{05299222741,
Author = {Seo, Sang-Woo and Cho, Sang-Yeon and Huang, Sa and Jokerst,
Nan Marie and Brown, April S.},
Title = {Pulse response tuning of high speed InGaAs thin film MSM
photodetector using external RCL loads},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {5726},
Pages = {52 - 60},
Address = {San Jose, CA, United States},
Year = {2005},
url = {http://dx.doi.org/10.1117/12.592246},
Keywords = {Semiconducting indium gallium arsenide;Thin film
devices;Frequency response;Semiconducting films;Light
transmission;Microwaves;Digital communication
systems;Natural frequencies;Inductance;Capacitance;Millimeter
waves;},
Abstract = {Practical, packaged photodetectors (PDs) must be interfaced
to bias and transmission lines, which introduce parasitics.
These parasitics (resistance, capacitance and inductance)
can be used to shape the temporal and frequency response of
packaged photodetectors. Thus, the bias circuitry, external
passives, and high speed interconnections must be carefully
designed to produce the desired response in a packaged
photodetector. Applications dictate the desired PD
characteristics, which are generally either a flat frequency
response, or a fast, ring-free impulse response. In this
paper, the effects of the parasitic resistance, capacitance,
and inductance are studied to affect the intrinsic response
of photodetectors for a flat frequency response or a fast
ring-free impulse response. For the optical transmission of
microwave and millimeter wave RF signals, such as remote
antennas or radar arrays, a flat frequency response is
critical. A flat frequency response can be obtained from
controlled ringing in the temporal domain. This paper
explores the control of ringing in the temporal domain using
varied external loads. A fast fall time, ring-free pulse is
useful for digital communications applications where ringing
can degrade the bit error rate. Fourier transforms show that
a ring-free impulse response has a characteristic fall-off
at high frequencies. However, this fall-off is detrimental
for frequency domain applications, so the optimization
condition for the inductance and capacitance is different
for these applications. This paper explores the suppression
of the impulse response tail by varying the external
loads.},
Key = {05299222741}
}
@article{8249882,
Author = {Brown, A.S.},
Title = {Flat, cheap, and under control [electrochemical mechanical
planarization]},
Journal = {IEEE Spectr. (USA)},
Volume = {42},
Number = {1},
Pages = {40 - 5},
Year = {2005},
url = {http://dx.doi.org/10.1109/MSPEC.2005.1377874},
Keywords = {chemical mechanical polishing;electrolytic
polishing;planarisation;semiconductor device
manufacture;},
Abstract = {This paper describes Applied Material's wafer polishing
technology, called electrochemical mechanical planarization
(ECMP). ECMP is the answer to the problems of
electropolishing and chemical mechanical planarization (CMP)
of the chip-making process: manufacturing faster, more
powerful chips without obliterating their vanishing fine and
increasingly fragile features. It is designed to remove
excess copper from the top of a newly formed layer of wiring
on a chip without damaging the fragile insulation material,
called a dielectric, beneath it. ECMP combines aspects of
two other technologies, chemical mechanical planarization
(CMP) and electropolishing},
Key = {8249882}
}
@article{04198149916,
Author = {Huang, Zhaoran and Cha, Cheolung and Chen, Shuodan and Sarmiento, Tomas and Shen, J.J. and Jokerst, Nan M. and Brooke, Martin A. and May, Gary and Brown, April
S.},
Title = {InGaAs MSM Photodetectors Modeling Using DOE
Analysis},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {5178},
Pages = {148 - 155},
Address = {San Diego, CA, United States},
Year = {2004},
url = {http://dx.doi.org/10.1117/12.507337},
Keywords = {Semiconducting indium gallium arsenide;Photolithography;Bandwidth;Field
effect transistors;Electric field effects;Optical
links;Statistical methods;Optimization;Error
analysis;Mathematical models;},
Abstract = {Linear statistical models have been generated to predict the
performance of metal-semiconductor-metal (MSM) PDs for
multi-gigabit optical interconnections. The models estimate
the bandwidth and responsivity of the MSM PDs based on the
input factors: absorbing layer thickness, detector size,
finger widths and finger gaps. The design of experiments
(DOE) approach was employed to obtain the necessary data to
construct the models. Numerous samples were fabricated so
that multiple devices measurements could serve to both
construct and verify the linear statistical models. The MSM
PDs were fabricated from material with structure
InAlAs/InAlGaAs/InGaAs (2000A, 3000A or 5000A, absorbing
layer)/InAlAs. The MSM interdigitated fingers were
photolithographically defined with finger gaps and widths
varying as DOE parameters. A benzocyclobutene (BCB,
Cyclotene 35) layer was spin-coated onto all of the samples
as isolation from the probing pads. In the bandwidth
analysis, the detector size (S) and material thickness (T)
were investigated with a fixed finger width (1 μm) and
gap (1 μm). Taking the measured results of these
detectors in the design matrix, and using least square
regression, the model equations were derived as: Bandwidth
(GHz) = 12.87 - 0.065S - 3T - 0.02ST. After these equations
were developed, predictive calculated results from these
equations were then further used to predict and compare
measured results on devices that were not used in the
statistical model. This leads to an average deviation
between predicted and measured bandwidth of less than 5%. In
the responsivity analysis, the predictive calculation leads
to an average deviation less than 11%.},
Key = {04198149916}
}
@article{04348319510,
Author = {Seo, Sang-Woo and Cho, Sang-Yeon and Huang, Sa and Brown,
April S. and Jokerst, Nan Marie},
Title = {High speed InGaAs thin film MSM photodetector
characterization using a fiber-based electro-optic sampling
system},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {5353},
Pages = {48 - 56},
Address = {San Jose, CA, United States},
Year = {2004},
url = {http://dx.doi.org/10.1117/12.531681},
Keywords = {Semiconducting gallium compounds;Thin film
devices;Electrooptical devices;Optical fibers;Bandwidth;Microwaves;Photocurrents;Sampling;},
Abstract = {As optoelectronic devices increase in speed, the measurement
system used to characterize these devices must have
sufficient bandwidth and minimum parasitic loading during
test to accurately determine the intrinsic performance of
the device under test. Conventional electrical measurement
systems have an intrinsic bandwidth due to the available
components for test and have parasitic loading due to direct
electrical contact to the device under the test.
Electro-optic sampling is an excellent measurement technique
for characterizing ultra-fast devices because it has high
bandwidth, is non-contact, is non-destructive, and
relatively non-invasive. In this paper, an optical
fiber-based electrooptic sampling system is designed and
used for characterizing high speed InGaAs thin film MSM
photodetectors. A fiber laser which is operating at
λ=1556 nm was used for the sampling and excitation
beam. Optical fibers were used to connect each component in
the system for flexibility. InGaAs thin film MSM
photodetectors were fabricated and characterized. InGaAs
thin film MSM photodetectors were bonded onto a coplanar
strip line deposited on a benzocyclobutene (BCB)-coated
glass substrate for characterization. These thin film
photodetectors show high speed operation combined with high
responsivity and large detection area compared to P-i-N
photodetectors operating at similar speeds.},
Key = {04348319510}
}
@article{8072961,
Author = {Losurdo, M. and Giangregorio, M.M. and Bruno, G. and Brown,
A.S. and Doolittle, W.A. and Ptak, A.J. and Myers,
T.H.},
Title = {Surface potential measurements of doping and defects in
p-GaN},
Journal = {GaN and Related Alloys - 2003 Symposium (Mater. Res. Soc.
Symposium Proceedings Vol.798)},
Pages = {805 - 10},
Address = {Boston, MA, USA},
Year = {2004},
Keywords = {beryllium;dielectric function;ellipsometry;Fermi
level;gallium compounds;hydrogen;III-V semiconductors;magnesium;passivation;semiconductor
epitaxial layers;silicon;surface potential;wide band gap
semiconductors;},
Abstract = {The interaction of Be-, Mg-, and Si- doped GaN epitaxial
films with atomic hydrogen, produced by a remote r.f.
hydrogen plasma, is investigated. The kinetics of the
interaction is monitored in real time by spectroscopic
ellipsometry through the measurement of the variation of the
GaN pseudodielectric function. The passivation effect of
hydrogen is inferred by surface potential measurements using
scanning Kelvin probe microscopy (SKPM). It is found that
the interaction of GaN with hydrogen is a strong function of
both the type and level of the doping. Hydrogen treatment is
shown to lead to a strong variation of the surface potential
and, hence, of the Fermi level position, which is the result
of p-dopant passivation by hydrogen. A different interaction
of Mg and Be with atomic hydrogen is also observed and
monitored in real time by ellipsometry. SKPM is also used
for studying the interaction of defects in GaN with atomic
hydrogen},
Key = {8072961}
}
@article{04478466901,
Author = {Seo, Sang-Woo and Jokerst, Nan Marie and Cho, Sang-Yeon and Brown, April S. and Huang, Sa and Shin, Jeng Jung and Brooke, Martin A.},
Title = {High-speed large-area inverted InGaAs thin-film
metal-semiconductor-metal photodetectors},
Journal = {IEEE Journal on Selected Topics in Quantum
Electronics},
Volume = {10},
Number = {4},
Pages = {686 - 693},
Year = {2004},
url = {http://dx.doi.org/10.1109/JSTQE.2004.831677},
Keywords = {Thin films;Semiconducting indium compounds;Electrooptical
effects;Electronics packaging;Optical links;Substrates;Sampling;},
Abstract = {Inverted metal-semiconductor-metal (I-MSM) photodetectors,
which are thin-film MSMs with the growth substrate removed
and fingers on the bottom of the device (to eliminate finger
shadowing to enhance responsivity), are reported herein for
high-speed high-efficiency large-area photodetectors.
Reported herein are the highest speed vertically addressed
large-area (40-μm diameter) photodetectors reported to
date, which operate with a responsivity of 0.16 A/W and a
full-width half-maximum of less than 5 ps. Materials,
fabrication processes, heterogeneous integration, and
characterization of I-MSM photodetectors are presented in
this paper, as measured using a fiber-based electrooptic
sampling system. These large-area photodetectors are ideal
for vertically addressed high-speed optical links which need
alignment-tolerant packaging for cost sensitive
applications.},
Key = {04478466901}
}
@article{04168116486,
Author = {Triplett, Gregory E. and Brown, April S. and May, Gary
S.},
Title = {Charge modification in InAs/AlxGa1-xSb
HEMT structures},
Journal = {Journal of Crystal Growth},
Volume = {265},
Number = {1-2},
Pages = {47 - 52},
Year = {2004},
url = {http://dx.doi.org/10.1016/j.jcrysgro.2004.01.036},
Keywords = {High electron mobility transistors;Semiconductor quantum
wells;Doping (additives);Heterojunctions;Epitaxial
growth;Interfaces (materials);Fermi level;Carrier
concentration;Parameter estimation;Molecular beam
epitaxy;},
Abstract = {Intrinsic sheet charge levels in unintentionally doped
AlSb/InAs/AlSb quantum wells are reproducibly [similar to]
10<sup>12</sup>/cm<sup>2</sup>. While these levels are
suitable for depletion-mode operation, realizing
enhancement-mode devices ultimately depends on the ability
to significantly reduce sheet charge. In an effort to limit
carrier accumulation in the InAs quantum well, we have
studied the impact of the addition of a p-type, Be, doping
plane between the channel and the cap and the modification
of defect densities present in the films. Molecular beam
epitaxy (MBE) process conditions including substrate
temperature, Be-doping density, and doping plane spacing
above the quantum well were varied during growth of
InAs-Al<sub>x</sub>Ga<sub>1-x</sub>Sb high electron mobility
transistors (HEMTs) structures. Utilizing a 2
<sup>3</sup>-full factorial statistical experimental design
plus eight additional runs, the ranges for Be-doping
(0-2e12/cm<sup>2</sup>), substrate temperature
(350-420°C), and separation above the quantum well
(60-80A) were examined. Relationships between MBE process
conditions and transport properties in Be-doped
InAs-Al<sub>x</sub>Ga<sub>1-x</sub>Sb HEMT structures were
established. Among the process parameters investigated,
substrate temperature during Be-doping had the most
significant impact on 2DEG concentration. Substrate
temperature and sheet charge exhibited an inversely
proportional relationship, where increasing substrate
temperature resulted in decreasing sheet charge values. The
lowest charge with corresponding mobility was
6.6×10<sup>10</sup> at 6000cm<sup>2</sup>/V/s. ©
2004 Elsevier B.V. All rights reserved.},
Key = {04168116486}
}
@article{04308280107,
Author = {Losurdo, Maria and Giangregorio, Maria M. and Capezzuto, Pio and Bruno, Giovanni and Namkoong, Gon and Doolittle, W. Alan and Brown, April S.},
Title = {Interplay between GaN polarity and surface reactivity
towards atomic hydrogen},
Journal = {Journal of Applied Physics},
Volume = {95},
Number = {12},
Pages = {8408 - 8418},
Year = {2004},
url = {http://dx.doi.org/10.1063/1.1745124},
Keywords = {Hydrogen;Molecular beam epitaxy;Sapphire;Thin
films;Epitaxial growth;Heterojunctions;Electron
diffraction;Electron mobility;Spectroscopic analysis;X ray
diffraction;},
Abstract = {The polarity of GaN epitaxial films and its impact on the
interaction of GaN surfaces with atomic hydrogen were
discussed. GaN epilayers were grown by radio frequency
plasma molecular beam epitaxy (MBE) with both GaN and AlN
buffer layers. It was found that a different reaction rate
exists for N- and Ga-polar GaN with atomic hydrogen, with
N-polar GaN exhibiting greater reactivity. The results show
that Ga-polar GaN results from the use of AlN buffer layers
on sapphire when nitrided.},
Key = {04308280107}
}
@article{05108871846,
Author = {Seo, Sang-Woo and Cha, Cheolung and Cho, Sang-Yeon and Huang, Sa and Jokerst, Nan M. and Brooke, Martin A. and Brown, April S.},
Title = {Etch enhanced low capacitance, large area thin film InGaAs
metal-semiconductor-metal photodetectors},
Journal = {Conference Proceedings - Lasers and Electro-Optics Society
Annual Meeting-LEOS},
Volume = {1},
Pages = {222 - 223},
Address = {Rio Grande, Puerto Rico},
Year = {2004},
Keywords = {Plasma etching;Capacitance;Semiconducting gallium;Impulse
response;Semiconducting indium;Thin films;Adsorption;Photoresistors;Light
scattering;Threshold voltage;Metallizing;Diaphragms;Permittivity;},
Abstract = {The enhancement of the impulse response and capacitance
performance of thin film InGaAs metal-semiconductor-metal
(MSM) was carried out through etching. The capacitances of
the MSM were measured using scattering parameter
measurements using a lightwave component analyzer. The thin
film I-MSM photodetector cladding layers were etched while
leaving the adsorbing layers intact. The measured impulse
response results show improvement as the thickness of the
thin film I-MSMs decrease, which was correlated with the
reduction of the capacitance.},
Key = {05108871846}
}
@article{8066407,
Author = {Gon Namkoong and Doolittle, W.A. and Brown, A.S. and Losurdo, M. and Giangregorio, M.M. and Bruno,
G.},
Title = {Effect of buffer design on AlGaN/AlN/GaN heterostructures by
MBE},
Journal = {GaN and Related Alloys - 2003 Symposium (Mater. Res. Soc.
Symposium Proceedings Vol.798)},
Pages = {359 - 64},
Address = {Boston, MA, USA},
Year = {2004},
Keywords = {aluminium compounds;gallium compounds;III-V
semiconductors;molecular beam epitaxial growth;semiconductor
epitaxial layers;semiconductor growth;semiconductor
heterojunctions;surface topography;},
Abstract = {The effect of the buffer layers on the subsequent GaN
epitaxial layers and electrical properties of AlGaN/AlN/GaN
heterojunction structures nitrided at various temperatures
was investigated. For AlN buffer layers, two different
growth conditions of AlN buffer layers were introduced to
avoid Al droplets. We found that etch pit density and
structural quality of GaN epitaxial layer strongly depends
on the growth conditions of AlN buffer layers. When using a
double buffer layer (low temperature GaN on high temperature
AlN) for 200 °C nitridation, the etch pit density was
measured to high 10<sup>7</sup> cm<sup>-2</sup> in GaN
epitaxial layers. Furthermore, we observed that electrical
properties of AlGaN/AlN/GaN heterostructures depend on
growth conditions of buffer layers and nitridation
temperatures. The mobility in Al<sub>0.33</sub>Ga<sub>0.67</sub>N/AlN/GaN
structures grown on single AlN buffer layers for 200 °C
nitridation were 1300 cm<sup>2</sup>/Vs at a sheet charge of
1.6 × 10<sup>13</sup> cm<sup>-2</sup>. Using the
double buffer layer for 200 °C nitridation, the mobility
increased to 1587 cm<sup>2</sup>/Vs with a sheet charge of
1.25 × 10<sup>13</sup> cm<sup>-2</sup>},
Key = {8066407}
}
@article{04108052618,
Author = {Losurdo, Maria and Giuva, Danilo and Bruno, Giovanni and Huang, Sa and Kim, Tong-Ho and Brown, April
S.},
Title = {The surface modification and reactivity of LiGaO2
substrates during GaN epitaxy},
Journal = {Journal of Crystal Growth},
Volume = {264},
Number = {1-3},
Pages = {139 - 149},
Year = {2004},
url = {http://dx.doi.org/10.1016/j.jcrysgro.2004.01.018},
Keywords = {Gallium nitride;Molecular beam epitaxy;Nitrides;Reaction
kinetics;Nitrogen;Ellipsometry;Hydrogen;Etching;Metallorganic
chemical vapor deposition;Vaporization;X ray photoelectron
spectroscopy;Atomic force microscopy;Reflection high energy
electron diffraction;},
Abstract = {The chemistry and kinetics of lithium gallate (LGO)
substrates during nitridation are investigated. Nitridation
experiments have been carried out using two remote nitrogen
RF plasma sources: in an MBE system and in a remote plasma
MOCVD system. The difference between the two nitrogen
sources is the pressure. The experiments were run in
parallel to demonstrate that the same heterogeneous
chemistry applies during LGO nitridation in both MBE and
MOCVD environments, provided that the same species is
produced in the gas phase. Surface analysis techniques,
including X-ray photoelectron spectroscopy (XPS), atomic
force microscopy (AFM) and spectroscopic ellipsometry (SE),
show that an optimal temperature of about 600°C and an
optimal time that depends on the incident nitrogen density
exists that results in the formation of [similar to] 5A of
GaN on LGO. The nitridation process competes with lattice
damage that is enhanced by the presence of hydrogen. ©
2004 Elsevier B.V. All rights reserved.},
Key = {04108052618}
}
@article{04368342647,
Author = {Losurdo, M. and Giangregorio, M.M. and Capezzuto, P. and Bruno, G. and Namkoong, G. and Doolittle, W.A. and Brown,
A.S.},
Title = {Interaction of GaN epitaxial layers with atomic
hydrogen},
Journal = {Applied Surface Science},
Volume = {235},
Number = {3},
Pages = {267 - 273},
Address = {Ustron, Poland},
Year = {2004},
url = {http://dx.doi.org/10.1016/j.apsusc.2004.05.152},
Keywords = {Epitaxial growth;Hydrogen;Sapphire;Ion bombardment;Passivation;Thin
films;Atomic force microscopy;Ellipsometry;Probes;},
Abstract = {GaN surface passivation processes are still under
development and among others hydrogen treatments are
investigated. In this study, we use non-destructive optical
and electrical probes such as spectroscopic ellipsometry
(SE) and surface potential Kelvin probe microscopy (SP-KPM)
in conjunction with non-contact atomic force microscopy
(AFM) for the study of the different reactivity of Ga-polar
and N-polar GaN epitaxial layers with atomic hydrogen. The
GaN epitaxial layers are grown by molecular beam epitaxy on
sapphire (0001) substrates, and GaN and AlN buffer layers
are used to grow N-polar and Ga-polar films, respectively.
The atomic hydrogen is produced by a remote rf (13.56MHz)
H<sub>2</sub> plasma in order to rule out any ion
bombardment of the GaN surface and make the interaction
chemical. It is found that the interaction of GaN surfaces
with atomic hydrogen depends on polarity, with N-polar GaN
exhibiting greater reactivity. Furthermore, it is found that
atomic hydrogen is effective in the passivation of grain
boundaries and surface defects states. © 2004 Elsevier
B.V. All rights reserved.},
Key = {04368342647}
}
@article{04438417380,
Author = {Brown, April S. and Losurdo, Maria and Bruno, Giovanni and Brown, Terence and May, Gary},
Title = {Fundamental reactions controlling anion exchange during the
synthesis of Sb/As mixed-anion heterojunctions},
Journal = {Journal of Vacuum Science and Technology B: Microelectronics
and Nanometer Structures},
Volume = {22},
Number = {4},
Pages = {2244 - 2249},
Year = {2004},
url = {http://dx.doi.org/10.1116/1.1775201},
Keywords = {Arsenic;Antimony;Reaction kinetics;Heterojunctions;Semiconducting
gallium compounds;Dimers;Molecular structure;Molecular beam
epitaxy;Synthesis (chemical);Scanning tunneling microscopy;X
ray photoelectron spectroscopy;Mathematical
models;},
Abstract = {As/Sb and Sb/As anion exchange reactions to control
heterojunction interface intermixing in mixed anion
structure were investigated. The substrate temperature,
anion flux exposure time, and incident anion molecular
species were analyzed. The characterization of Sb/AS
structures was done by Sb surface segregation and subsequent
incorporate in epitaxial overlayers. The result show that
As/Sb exchange was significant and enhanced by the use of
dimer fluxes.},
Key = {04438417380}
}
@article{04208160908,
Author = {Losurdo, M. and Giuva, D. and Giangregorio, M.M. and Bruno,
G. and Brown, A.S.},
Title = {Spectroscopic ellipsometry characterization of interface
reactivity in GaAs-based superlattices},
Journal = {Thin Solid Films},
Volume = {455-456},
Pages = {457 - 461},
Address = {Vienna, Austria},
Year = {2004},
url = {http://dx.doi.org/10.1016/j.tsf.2003.11.286},
Keywords = {Superlattices;Ion exchange;Negative ions;Surface
treatment;Ternary systems;Microstructure;Ellipsometry;Spectroscopic
analysis;Molecular beam epitaxy;},
Abstract = {Pseudodielectric function spectra of GaAs/GaSb<sub>1-y</sub>As<sub>y</sub>,
GaSb/GaAs<sub>y</sub>Sb<sub>1-y</sub> and
GaAs/GaP<sub>y</sub>As<sub>1-y</sub> superlattices have been
measured by spectroscopic ellipsometry in the 0.75-5.5 eV
photon energy range. The analysis of the E<sub>1</sub>
interband critical point and modeling of spectra has been
carried out to investigate the chemistry of the anion
exchange reaction and abruptness of interface composition in
the superlattices. It has been found that a ternary compound
GaP<sub>y</sub>As <sub>1-y</sub> forms in the case of the
P-for-As anion exchange reaction. In the case of As-for-Sb
anion exchange reaction for (GaSb/GaAs<sub>y</sub>Sb
<sub>1-y</sub>)<sub>20</sub> SLs, SE data show that this
anion exchange results in the formation not only of a
ternary alloy GaAs<sub>y</sub>Sb<sub>1-y</sub>, but also in
the formation of isoelectronic compounds AsSb<sub>x</sub>
that segregate at the GaSb/GaAs interface. In the case of
Sb-for-As anion exchange for (GaAs/GaSbyAs<sub>1-y</sub>)<sub>20</sub>
SLs, Sb segregates at the GaAs surface. © 2003 Elsevier
B.V. All rights reserved.},
Key = {04208160908}
}
@article{04278245174,
Author = {Losurdo, M. and Giangregorio, M.M. and Bruno, G. and Brown,
A.S. and Doolittle, W.A. and Namkoong, Gon and Ptak, A.J. and Myers, T.H.},
Title = {Surface potential measurements of doping and defects in
p-GaN},
Journal = {Materials Research Society Symposium - Proceedings},
Volume = {798},
Pages = {805 - 810},
Address = {Boston, MA, United States},
Year = {2003},
Keywords = {Doping (additives);Surface measurement;Kinetic theory;Fermi
level;Silicon;Spectroscopy;Ellipsometry;Passivation;Beam
plasma interactions;Beryllium;Hydrogen;Magnesium printing
plates;},
Abstract = {The interaction of Be-, Mg-, and Si- doped GaN epitaxial
films with atomic hydrogen, produced by a remote r.f.
hydrogen plasma, is investigated. The kinetics of the
interaction is monitored in real time by spectroscopic
ellipsometry through the measurement of the variation of the
GaN pseudodielectric function. The passivation effect of
hydrogen is inferred by surface potential measurements using
scanning Kelvin probe microscopy (SKPM). It is found that
the interaction of GaN with hydrogen is a strong function of
both the type and level of the doping. Hydrogen treatment is
shown to lead to a strong variation of the surface potential
and, hence, of the Fermi level position, which is the result
of p-dopant passivation by hydrogen. A different interaction
of Mg and Be with atomic hydrogen is also observed and
monitored in real time by ellipsometry. SKPM is also used
for studying the interaction of defects in GaN with atomic
hydrogen.},
Key = {04278245174}
}
@article{04498701808,
Author = {Seo, S.W. and Shen, J.J. and Jokerst, N.M. and Brown,
A.S.},
Title = {Large area, high speed InGaAs thin film MSMs for
heterogeneously integrated optoelectronics},
Journal = {OSA Trends in Optics and Photonics Series},
Volume = {88},
Pages = {460 - 463},
Address = {Baltimore, MD, United States},
Year = {2003},
Keywords = {Optoelectronic devices;Thin films;Fiber optics;Electrodes;Indium
compounds;Gallium compounds;Diaphragms;Quantum
efficiency;Metallizing;Degradation;},
Abstract = {Thin film InGaAs photodetectors for heterogeneously
integrated optoelectronics are demonstrated with low dark
current (0.16nA at 5V), and high speed (3ps rise time, 6.3ps
FWHM), large area (40 μm), and good responsivity (0.19A/W
at 5V).},
Key = {04498701808}
}
@article{03157430661,
Author = {Namkoong, Gon and Doolittle, W. Alan and Brown, April S. and Losurdo, Maria and Giangregorio, Maria M. and Bruno,
Giovanni},
Title = {The impact of substrate nitridation temperature and buffer
design and synthesis on the polarity of GaN epitaxial
films},
Journal = {Journal of Crystal Growth},
Volume = {252},
Number = {1-3},
Pages = {159 - 166},
Year = {2003},
url = {http://dx.doi.org/10.1016/S0022-0248(03)00953-9},
Keywords = {Epitaxial growth;Sapphire;Morphology;Annealing;Dislocations
(crystals);Substrates;Atomic force microscopy;},
Abstract = {The polarity of GaN epitaxial layers grown on GaN and AlN
buffer layers was investigated and found to be dependent on
nitridation temperature over the range of 200-700°C.
When low temperature (LT), 500°C, GaN buffer layers are
used, GaN epitaxial layers grown on 200°C nitrided
sapphire have a higher density of N-polar inversion domains.
However, a high density of dislocation pits was observed on
GaN epitaxial layers based on AFM morphology when GaN
epitaxial layers were grown on LT GaN buffer of 700°C
nitrided sapphire substrate. With high temperature (HT),
850°C, AlN buffer layers, the density of N-polar
inversion domains in GaN epitaxial layers depends on the
thickness of AlN buffer layer. The structural quality of
Ga-polar GaN epitaxial layer is dramatically improved when
LT GaN and HT AlN buffer layers are combined with an
optimized annealing time. The measured full-widths at
half-maximum of (0002) symmetric and (10.4) asymmetric
reflections are 68 and 246 arcsec, respectively, for 1.0
μm GaN epitaxial layers. The results presented here can
be implemented to produce low dislocation density, single
Ga-polar GaN epitaxial layers. © 2003 Elsevier Science
B.V. All rights reserved.},
Key = {03157430661}
}
@article{7775917,
Author = {Kuech, T.F. and Ning Liu and Tong-Ho Kim and Changhyun Yi and Brown, A.S.},
Title = {Alternative substrates for InP and related
materials},
Journal = {2003 International Conference Indium Phosphide and Related
Materials. Conference Proceedings (Cat. No.03CH37413)},
Pages = {562 -},
Address = {Santa Barbara, CA, USA},
Year = {2003},
url = {http://dx.doi.org/10.1109/ICIPRM.2003.1205442},
Keywords = {gallium arsenide;III-V semiconductors;indium
compounds;substrates;wafer bonding;},
Abstract = {We will present examples of wafer bonding as applied to
InGaAs/InP system highlighting the effects of the bonding
process on the post-bonding device characteristics. Some
future directions of alternative substrates for use in InP
technologies will be presented},
Key = {7775917}
}
@article{03447702287,
Author = {Doolittle, W. Alan and Namkoong, Gon and Carver, Alexander
G. and Brown, April S.},
Title = {Challenges and potential payoff for crystalline oxides in
wide bandgap semiconductor technology},
Journal = {Solid-State Electronics},
Volume = {47},
Number = {12},
Pages = {2143 - 2147},
Year = {2003},
url = {http://dx.doi.org/10.1016/S0038-1101(03)00187-4},
Keywords = {Crystals;Oxides;Permittivity;Polarization;},
Abstract = {While growth of wide bandgap semiconductor materials on
crystalline oxides (sapphire, lithium gallate, lithium
aluminate, zinc oxide and others) has become routine, growth
of crystalline oxides on wide bandgap materials remains
challenging and minimally explored. The potential payoff in
terms of enhanced device performance, increased
functionality and reliability warrants examining this
option. This presentation aims at targeting key areas, where
crystalline oxides could improve wide bandgap semiconductor
device performance. Some of these include the use of
ferroelectric oxides for power switching applications,
oxides with anisotropic dielectric constants for high
voltage termination and oxides with large electric flux
density near breakdown. Unique polarization engineered
structures are described that are enabled by using
lithographically defined poled regions in a ferroelectric
substrate. The desired crystalline oxide properties,
potential implementation challenges and potential pitfalls
will be discussed. © 2003 Published by Elsevier
Ltd.},
Key = {03447702287}
}
@article{04288257335,
Author = {Losurdo, Maria and Giuva, Danilo and Capezzuto, Pio and Bruno, Giovanni and Brown, Terence and Triplett, Greg and May, Gary and Brown, April S.},
Title = {A study of anion exchange reactions at GaAs surfaces for
heterojunction interface control},
Journal = {Materials Research Society Symposium - Proceedings},
Volume = {799},
Pages = {97 - 102},
Address = {Boston, MA, United States},
Year = {2003},
Keywords = {Semiconducting gallium arsenide;Heterojunctions;Superlattices;Diffusion
in solids;Energy gap;Negative ions;X ray photoelectron
spectroscopy;},
Abstract = {GaP<sub>y</sub>As<sub>1-y</sub>/GaAs, GaAs<sub>y</sub>Sb<sub>i-y</sub>/GaSb
and GaSb<sub>y</sub>As<sub>1-y</sub>/GaAs superlattices
(SLs) grown by MBE, by exposure of GaAs to phosphorus and
antimonide fluxes, and by exposure of GaSb to an arsenic
flux, respectively, have been investigated. The focus is on
the abruptness of interfaces and understanding the
mechanisms associated with anion incorporation and exchange.
In the case of the Sb flux interaction with the GaAs
surface, the Sb segregation at the GaAs surface inhibits
anion exchange. For the case of As over GaSb reactions,
anion exchange results in the formation not only of the
ternary alloy GaAs<sub>y</sub>Sb<sub>1-y</sub>, but also of
isoelectronic compounds AsSb<sub>x</sub> that segregate at
the GaSb/GaAs interface. In the case of the P flux
interfaction with the GaAs surface, fast in-diffusion of P
results in graded GaP<sub>y</sub>As<sub>1-y</sub> layer
formation.},
Key = {04288257335}
}
@article{04278245113,
Author = {Namkoong, Gon and Doolittle, W. Alan and Brown, A.S. and Losurdo, M. and Giangregorio, M.M. and Bruno,
G.},
Title = {Effect of buffer design on AlGaN/AlN/GaN heterostrucutres by
MBE},
Journal = {Materials Research Society Symposium - Proceedings},
Volume = {798},
Pages = {359 - 364},
Address = {Boston, MA, United States},
Year = {2003},
Keywords = {Heterojunctions;Epitaxial growth;Crystal lattices;Organic
acids;Desorption;Carrier concentration;X ray
diffraction;Reflection high energy electron
diffraction;},
Abstract = {The effect of the buffer layers on the subsequent GaN
epitaxial layers and electrical properties of AlGaN/AlN/GaN
heterojunction structures nitrided at various temperatures
was investigated. For AlN buffer layers, two different
growth conditions of AlN buffer layers were introduced to
avoid Al droplets. We found that etch pit density and
structural quality of GaN epitaxial layer strongly depends
on the growth conditions of AlN buffer layers. When using a
double buffer layer (low temperature GaN on high temperature
AlN) for 200 °C nitridation, the etch pit density was
measured to high 107 cm<sup>-2</sup> in GaN epitaxial
layers. Furthermore, we observed that electrical properties
of AlGaN/AlN/GaN heterostructures depend on growth
conditions of buffer layers and nitridation temperatures.
The mobility in Al<sub>0.33</sub>Ga <sub>0.67</sub>N/AlN/GaN
structures grown on single AlN buffer layers for 200 °C
nitridation were 1300 cm<sup>2</sup>/Vs at a sheet charge of
1.6×10<sup>13</sup> cm<sup>-2</sup>. Using the double
buffer layer for 200 °C nitridation, the mobility
increased to 1587 cm<sup>2</sup>/Vs with a sheet charge of
1.25×10<sup>13</sup> cm<sup>-2</sup>.},
Key = {04278245113}
}
@article{7648070,
Author = {Brown, A.S.},
Title = {Superconducting circuit makers pin hopes on wireless
filters},
Journal = {IEEE Spectr. (USA)},
Volume = {40},
Number = {4},
Pages = {3 pp. -},
Year = {2003},
Keywords = {superconducting filters;},
Abstract = {The discovery of ceramic superconductors in 1986 sparked
dreams of levitating trains, cheap electric power, and
desktop medical scanners. Some savvy investors instead set
their sights on superconducting microelectronics. In 1987, a
group that included Intel cofounder Robert Noyce and Nobel
Laureate J. Robert Schrieffer started Superconductor
Technologies Inc. (STI). In the same year another group, led
by Ethernet pioneer John F. Shoch, started Conductus Inc.
Now, 15 years later, the pioneers in superconducting
circuits have merged in the hopes of better surviving a
market meltdown. By the time the two companies merged with
one another, their visions of becoming a foundry for
superconducting circuits in general had narrowed to
production of superconducting filters to improve cell phone
communications},
Key = {7648070}
}
@article{02176925920,
Author = {Yi, Changhyun and Kim, Tong-Ho and Brown, April
S.},
Title = {InP-based AlInAs/GaAs0.51Sb0.49/GaInAs
single heterojunction bipolar transistor for high-speed and
RF wireless applications},
Journal = {Journal of Electronic Materials},
Volume = {31},
Number = {2},
Pages = {95 - 98},
Year = {2002},
Keywords = {Semiconducting aluminum compounds;Semiconducting gallium
arsenide;Semiconducting indium gallium arsenide;Heterojunction
bipolar transistors;Semiconductor growth;Molecular beam
epitaxy;Integrated circuit manufacture;Semiconductor device
structures;Application specific integrated circuits;Electric
potential;Electric currents;Current density;},
Abstract = {The InP-based AlInAs-GaAsSb-GaInAs heterojunction bipolar
transistors (HBTs) have been grown by solid-source
molecular-beam epitaxy (SSMBE). Since the AlInAs-GaAsSb
heterojunction has a type-II (staggered) band lineup, the
conduction-band discontinuity is negligible at 300 K (10
meV). Thus, the turn-on voltage is significantly lower than
that of an AlInAs-GaInAs HBT even without compositional
grading of the emitter-base junction. A self-aligned process
was used to fabricate large area devices. The measured
turn-on voltage and collector-emitter offset were 0.36 V and
0.23 V, respectively, with a DC gain of approximately 25 and
ideality factors of η<sub>C</sub> = 1.01 and
η<sub>B</sub> = 1.1 at J<sub>C</sub> = 10
kA/cm<sup>2</sup> collector-current density.},
Key = {02176925920}
}
@article{7636394,
Author = {Losurdo, M. and Giangregorio, M.M. and Capezzuto, P. and Bruno, G. and Namkoong, G. and Doolittle, W.A. and Brown,
A.S.},
Title = {A chemical perspective of GaN polarity: the use of hydrogen
plasma dry etching versus NaOH wet etching to determine
polarity},
Journal = {Materials and Devices for Optoelectronics and
Microphotonics. Symposia (Materials Research Society
Symposium Proceedings Vol.722)},
Pages = {103 - 8},
Address = {San Francisco, CA, USA},
Year = {2002},
Keywords = {dislocation density;domains;gallium compounds;III-V
semiconductors;semiconductor epitaxial layers;sputter
etching;surface morphology;wide band gap
semiconductors;},
Abstract = {The use of dry hydrogen plasma etching is evaluated for
determination of GaN polarity and critically compared to wet
etching in NaOH. It is shown that hydrogen plasma etching is
effective in revealing inversion domains (IDs) and some
types of dislocations. This is because the surface
morphology is unchanged by the hydrogen treatment, and,
hence, the surface reactivity is not masked},
Key = {7636394}
}
@article{02166923808,
Author = {Losurdo, M. and Capezzuto, P. and Bruno, G. and Namkoong, G. and Doolittle, W.A. and Brown, A.S.},
Title = {Plasmas for the low-temperature growth of high-quality GaN
films by molecular beam epitaxy and remote plasma
MOCVD},
Journal = {Physica Status Solidi (A) Applied Research},
Volume = {190},
Number = {1},
Pages = {43 - 51},
Year = {2002},
url = {http://dx.doi.org/10.1002/1521-396X(200203)190:1<43::AID-PSSA43>3.0.CO;2-G},
Keywords = {Gallium nitride;Film growth;Sapphire;Plasmas;Molecular beam
epitaxy;Metallorganic chemical vapor deposition;Annealing;Interferometry;Ellipsometry;Electron
spectroscopy;Reflection high energy electron
diffraction;},
Abstract = {GaN heteroepitaxial growth on sapphire (0001) substrates was
carried out by both radio-frequency (rf) remote plasma
metalorganic chemical vapor deposition (RP-MOCVD) and
molecular beam epitaxy (MBE). A multistep growth process
including substrate plasma cleaning and nitridation, buffer
growth, its subsequent annealing and epilayer growth was
used. In order to achieve a better understanding of the GaN
growth, in-situ real time investigation of the surface
chemistry is performed for all the steps using the
conventional reflection high-energy electron spectroscopy
(RHEED) during the MBE process, while laser reflectance
interferometry (LRI) and spectroscopic ellipsometry (SE),
which do not require UHV conditions, are used for the
monitoring of the RP-MOCVD process. The chemistry of the rf
N<sub>2</sub> plasma sapphire nitridation and its effect on
the epilayer growth and quality are discussed in both MBE
and RP-MOCVD.},
Key = {02166923808}
}
@article{03317575949,
Author = {Doolittle, W. Alan and Namkoong, Gon and Carver, Alexander and Henderson, Walter and Jundt, Dieter and Brown, April
S.},
Title = {III-nitride growth on lithium niobate: A new substrate
material for polarity engineering in III-nitride
heteroepitaxy},
Journal = {Materials Research Society Symposium - Proceedings},
Volume = {743},
Pages = {9 - 14},
Address = {Boston, MA, United States},
Year = {2002},
Keywords = {Nitrides;Semiconductor growth;Epitaxial growth;Heterojunctions;Substrates;Crystal
lattices;Film growth;Molecular beam epitaxy;Gallium
nitride;Aluminum nitride;Nonlinear optics;Optical
properties;},
Abstract = {Herein, we discuss the use of a novel new substrate for
III-Nitride epitaxy, Lithium Niobate. It is shown that
Lithium Niobate (LN) has a smaller lattice mismatch to
III-Nitrides than sapphire and can be used to control the
polarity of III-Nitride films grown by plasma assisted
molecular beam epitaxy. Results from initial growth studies
are reported including using various nitridation/buffer
conditions along with structural and optical
characterization. Comparisons of data obtained from GaN and
A1N buffer layers are offered and details of the film
adhesion dependence on buffer layer conditions is presented.
Lateral polarization heterostructures grown on periodically
poled LN are also demonstrated. While work is still required
to establish the limits of the methods proposed herein,
these initial studies offer the promise for mixing
Ill-Nitride semiconductor materials with lithium niobate
allowing wide bandgap semiconductors to utilize the
acoustic, pyroelectric/ferroelectric, electro-optic, and
nonlinear optical properties of this new substrate material
as well as the ability to engineer various polarization
structures for future devices.},
Key = {03317575949}
}
@article{02106879531,
Author = {Namkoong, Gon and Brown, April S. and Losurdo, Maria and Capezzuto, Pio and Bruno, Giovanni and Alan Doolittle,
W.},
Title = {Role of sapphire nitridation temperature on GaN growth by
plasma assisted molecular beam epitaxy: Part I. Impact of
the nitridation chemistry on material characteristics},
Journal = {Journal of Applied Physics},
Volume = {91},
Number = {4},
Pages = {2499 -},
Year = {2002},
url = {http://dx.doi.org/10.1063/1.1435834},
Key = {02106879531}
}
@article{02477214629,
Author = {Wang, Zhong L. and Brown, April S. and Wang, Y.Q. and Shen,
J.J.},
Title = {Engineering vertically aligned InAs/GaAs quantum dot
structures via anion exchange},
Journal = {Solid State Communications},
Volume = {122},
Number = {10},
Pages = {553 - 556},
Year = {2002},
url = {http://dx.doi.org/10.1016/S0038-1098(02)00212-0},
Keywords = {Semiconducting gallium arsenide;Negative ions;Self
assembly;Crystal growth;Molecular beam epitaxy;Morphology;},
Abstract = {P/As anion exchange is exploited to modify stacked InAs/GaAs
quantum dot structures grown by molecular beam epitaxy
(MBE). It is shown that the vertical alignment and size
uniformity can be remarkably improved via P/As anion
exchange. This, therefore, demonstrates a promising approach
to tuning the quantum dot morphologies and structures, and
hence, the electronic and optoelectronic properties. ©
2002 Elsevier Science Ltd. All rights reserved.},
Key = {02477214629}
}
@article{7402750,
Author = {Triplett, G.E. and May, G.S. and Brown, A.S.},
Title = {Using neural networks for RHEED modeling of interfaces in
AlGaSb-InAs HEMT devices},
Journal = {2002 GaAs MANTECH Conference. Digest of Papers},
Pages = {157 - 60},
Address = {San Diego, CA, USA},
Year = {2002},
Keywords = {aluminium compounds;gallium compounds;high electron mobility
transistors;III-V semiconductors;indium compounds;neural
nets;reflection high energy electron diffraction;semiconductor
device models;},
Abstract = {In this paper, it is demonstrated that RHEED data obtained
during the formation of the interfaces in AlGaSb-InAs HEMT
devices can be used to model device important epitaxial
layer electrical performance parameters. RHEED intensity
oscillations of the specular spot are analyzed using
principle component analysis (PCA) and modeled using error
backpropagation (BP) neural networks},
Key = {7402750}
}
@article{02377085936,
Author = {Yi, Changhyun and Metzger, Robert A. and Brown, April
S.},
Title = {The effect of strained Al0.7In0.3As
emitter layers on abrupt N-p+ AlInAs-GaInAs
heterojunction diodes and heterojunction bipolar
transistors},
Journal = {Journal of Electronic Materials},
Volume = {31},
Number = {8},
Pages = {841 - 847},
Year = {2002},
Keywords = {Semiconducting aluminum compounds;Semiconductor
diodes;Heterojunction bipolar transistors;Computer
simulation;Electric field effects;Molecular beam
epitaxy;Electron transport properties;Carrier
concentration;Thermionic emission;Electron
tunneling;Electron mobility;Band structure;},
Abstract = {Strained Al<sub>x</sub>In<sub>1-x</sub>As/Ga<sub>0.47</sub>In<sub>0.53</sub>As
heterojunction N-p<sup>+</sup> diodes and heterojunction
bipolar transistors (HBTs) have been grown on InP substrates
by solid-source molecular-beam epitaxy, fabricated, and
characterized. To determine the effects of the
conduction-band discontinuity at the emitter-base
heterojunction on turn-on voltage and ideality factor, a
strained Al<sub>0.7</sub>In<sub>0.3</sub>As layer is
inserted in the emitter near the base. Changes in transport
across the junction are observed as a function of the
strained-layer position and thickness. These results were
used to implement strained emitter HBTs.},
Key = {02377085936}
}
@article{02307028319,
Author = {Namkoong, Gon and Doolittle, W. Alan and Brown, April S. and Losurdo, Maria and Capezzuto, Pio and Bruno,
Giovanni},
Title = {Role of low-temperature (200 °C) nitridation in the
growth of GaN by plasma-assisted molecular-beam
epitaxy},
Journal = {Journal of Vacuum Science and Technology B: Microelectronics
and Nanometer Structures},
Volume = {20},
Number = {3},
Pages = {1221 - 1228},
Address = {Providence, RI},
Year = {2002},
url = {http://dx.doi.org/10.1116/1.1470514},
Keywords = {Gallium nitride;Molecular beam epitaxy;Nitriding;Sapphire;Surface
chemistry;Optical properties;Diffusion;Low temperature
effects;High temperature effects;Ellipsometry;X ray
photoelectron spectroscopy;Secondary ion mass
spectrometry;},
Abstract = {The effects of sapphire nitridation temperature on the
properties of GaN grown by radiofrequency (rf) plasma
assisted molecular-beam epitaxy (MBE) were discussed. It was
found that the optical and structural characteristics of GaN
epitaxial layers were dramatically improved at a nitridation
temperatutre of 200 °C. The analysis showed that the
nitridation temperature was a crucial parameter in
improvement of the optical and structural quality of GaN
epitaxial layers.},
Key = {02307028319}
}
@article{03467727853,
Author = {Kim, Tong-Ho and Yi, Changhyun and Brown, April S. and Moran, Peter and Kuech, Thomas},
Title = {The Heterogeneous Integration of InAlAs/InGaAs
Heterojunction Diodes on GaAs: Impact of Wafer Bonding on
Structural and Electrical Characteristics},
Journal = {Proceedings IEEE Lester Eastman Conference on High
Performance Devices},
Pages = {384 - 392},
Address = {Newark, DE, United States},
Year = {2002},
Keywords = {Semiconducting gallium arsenide;Semiconducting indium
gallium arsenide;Current voltage characteristics;X ray
diffraction analysis;Secondary ion mass spectrometry;Computer
simulation;},
Abstract = {We have investigated the influence of low temperature wafer
bonding on the electrical and structural characteristics of
InAlAs/InGaAs n-p heterojunction structures with similar
structure to an emitter-base junction of InAlAs/InGaAs HBTs.
Those n-p junction heterostructures were grown on an InP
(100) substrate by solid source MBE. The effect of the wafer
bonding process on the structural properties of the
epitaxial layers was studied by comparing triple crystal
x-ray diffraction measurements and simulations before and
after bonding. In addition, the influence of the bonding
process on the electrical properties of the heterojunction
structures was assessed through SIMS analysis of both the
bonded and non-bonded samples and an analysis of the I-V
characteristics of diodes fabricated on both the bonded and
non-bonded sample. These analyses show that the structural
and electrical properties of the as-grown epitaxial layers
were negligibly changed by the low temperature wafer
transfer process.},
Key = {03467727853}
}
@article{02216955072,
Author = {Seo, Sangwoo and Kang, Sangbeom and Doolittle, William A. and Lee, K.K. and Huang, S. and Jokerst, N.M. and Brown,
A.S. and Brooke, M.A.},
Title = {The heterogeneous integration of GaN thin-film
metal-semiconductor-metal photodetectors onto
silicon},
Journal = {IEEE Photonics Technology Letters},
Volume = {14},
Number = {2},
Pages = {185 - 187},
Year = {2002},
url = {http://dx.doi.org/10.1109/68.980507},
Keywords = {Thin film devices;Gallium nitride;Semiconducting
silicon;Silica;Low temperature operations;Etching;Substrates;Lithium
compounds;Molecular beam epitaxy;},
Abstract = {The heterogeneous integration of GaN thin-film
metal-semiconductor-metal (MSM) photodetectors onto a host
substrate of SiO<sub>2</sub>-Si is reported herein.
Thin-film GaN photodetectors were separated from the lithium
gallate (LiGaO<sub>2</sub>) growth substrate using selective
etching, and contact bonded onto an SiO<sub>2</sub>-Si host
substrate. The thin-film MSMs exhibited a dark current of
13.36 pA and an UV photoresponse at 308 nm of 0.11 A/W at a
reverse bias voltage of 20 V. This first demonstration of
GaN thin-film device integration onto SiO<sub>2</sub>-Si
using a low-temperature integration process, combined with
the advances in GaN material quality on LiGaO<sub>2</sub>
substrates, enables the integration of GaN devices with Si
circuitry for heterogeneously integrated
systems.},
Key = {02216955072}
}
@article{7160044,
Author = {Losurdo, M. and Capezzuto, P. and Bruno, G. and Namkoong, G. and Doolittle, W.A. and Brown, A.S.},
Title = {The chemistry of sapphire nitridation in relation to the GaN
structural quality: Why low temperature 200°C
nitridation?},
Journal = {Phys. Status Solidi A (Germany)},
Volume = {188},
Number = {2},
Pages = {561 - 5},
Address = {Denver, CO, USA},
Year = {2001},
url = {http://dx.doi.org/10.1002/1521-396X(200112)188:2<561::AID-PSSA561>3.0.CO;2-J},
Keywords = {annealing;chemisorption;gallium compounds;III-V
semiconductors;nitridation;photoluminescence;sapphire;semiconductor
epitaxial layers;semiconductor growth;substrates;thermally
stimulated desorption;wide band gap semiconductors;},
Abstract = {The effect of c-plane sapphire nitridation upon exposure to
an rf N<sub>2</sub> plasma at temperatures in the range
100-700°C on the quality of GaN epilayers grown by MBE
is investigated. A homogeneous AlN layer is formed at
200°C. Nitridation at higher temperatures creates a
rough and non-homogeneous nitridated layer including both
AlN and NO. Lowering the nitridation temperature to
200°C results in the improvement of the GaN structural
and photoluminescence properties. The results are
interpreted in the framework of a chemical model based on
the competition between formation of AlN and NO whose
adsorption/desorption equilibrium on the sapphire surface
strongly depends on temperature},
Key = {7160044}
}
@article{7160030,
Author = {Doolittle, W.A. and Brown, A.S. and Kang, S. and Seo, S.W. and Huang, S. and Jokerst, N.M.},
Title = {Recent advances in III-nitride devices grown on lithium
gallate},
Journal = {Phys. Status Solidi A (Germany)},
Volume = {188},
Number = {2},
Pages = {491 - 5},
Address = {Denver, CO, USA},
Year = {2001},
url = {http://dx.doi.org/10.1002/1521-396X(200112)188:2<491::AID-PSSA491>3.0.CO;2-B},
Keywords = {diffusion;dislocation density;electron mobility;field effect
transistors;gallium compounds;getters;III-V
semiconductors;leakage currents;lithium compounds;photodiodes;semiconductor
epitaxial layers;semiconductor growth;substrates;wide band
gap semiconductors;},
Abstract = {We discuss recent advances in the growth of III-nitride
materials and devices, which include: (i) The reduction of
the near-surface threading dislocation density in GaN on
lithium gallate (LGO) to ≈2×10<sup>7</sup>
cm<sup>-2</sup>. (ii) The demonstration of GaN, 50×130
μm, metal-semiconductor-metal (MSM) photodiodes with
extremely low leakage current, 0.11 pA at 2 V and 7.9 pA at
60 V, and UV photoresponse at 308 nm and 20 V of 0.105 A/W.
(iii) State of the art MSM devices have been successfully
removed from the LGO substrate and attached to silicon
wafers with no degradation in current characteristics. (iv)
Demonstration of very thin, 0.7 μm HFET structures, grown
at a rapid rate of 0.9 μm/h, with near state of the art
room temperature 2DEG mobilities of 1365 cm<sup>2</sup>/Vs
at a sheet charge of 9×10<sup>12</sup>
cm<sup>-2</sup>. (v) The elimination of substrate impurity
diffusion by inclusion of gettering buffers has also been
demonstrated},
Key = {7160030}
}
@article{02106878467,
Author = {Brown, April S. and Jokerst, Nan Marie and Doolittle, Alan and Brooke, Martin and Kuech, Thomas F. and Seo, Sang-Woo and Kang, Sangbeom and Huang, Sa and Shen,
Jeng-Jung},
Title = {Heterogeneous integration: From substrate technology to
active packaging},
Journal = {Technical Digest - International Electron Devices
Meeting},
Pages = {197 - 200},
Address = {Washington, DC},
Year = {2001},
url = {http://dx.doi.org/10.1109/IEDM.2001.979465},
Keywords = {Semiconducting indium phosphide;Gallium nitride;Semiconducting
silicon;Dissimilar materials;Substrates;MIM devices;High
electron mobility transistors;Semiconducting indium gallium
arsenide;CMOS integrated circuits;Heterojunctions;Molecular
beam epitaxy;},
Abstract = {Heterogeneous integration of dissimilar materials and
devices is necessary for the continued advancement of
electronic and optoelectronic systems. A range of processes
has been developed in recent years that will enable system
integration and advanced packaging. Herein, we outline our
approaches towards heterogeneous integration.},
Key = {02106878467}
}
@article{01416680007,
Author = {Seo, S.W. and Lee, K.K. and Kang, S. and Huang, S. and Doolittle, W.A. and Jokerst, N.M. and Brown,
A.S.},
Title = {GaN metal-semiconductor-metal photodetectors grown on
lithium gallate substrates by molecular-beam
epitaxy},
Journal = {Applied Physics Letters},
Volume = {79},
Number = {9},
Pages = {1372 -},
Year = {2001},
url = {http://dx.doi.org/10.1063/1.1398320},
Key = {01416680007}
}
@article{01496751276,
Author = {Brown, A.S. and Doolittle, W.A. and Jokerst, N.M. and Kang,
S. and Huang, S. and Seo, S.W.},
Title = {Heterogeneous materials integration: Compliant substrates to
active device and materials packaging},
Journal = {Materials Science and Engineering B: Solid-State Materials
for Advanced Technology},
Volume = {87},
Number = {3},
Pages = {317 - 322},
Year = {2001},
url = {http://dx.doi.org/10.1016/S0921-5107(01)00730-9},
Keywords = {Epitaxial growth;Crystal defects;Microelectronics;Substrates;Crystal
lattices;},
Abstract = {The drive for the heterogeneous integration of materials has
led to significant advances in materials and device
processing, and in the understanding of defect production
and control during epitaxy. Heterogeneous integration is
driven by microelectronic and packaging trends, and the
advent of new materials, such as GaN, that do not possess
native substrates. During the last decade, these objectives
led to research in the development of compliant substrates.
While the ideal compliant substrate concept and
implementation may be flawed, this research has certainly
advanced materials integration technology. This paper will
provide an overview of recent results in compliant substrate
experiments and interpretation, and the related advancement
of materials and device integration and packaging deriving
from some of this research. © 2001 Published by
Elsevier Science B.V.},
Key = {01496751276}
}
@article{02427144459,
Author = {Shen, Jeng-Jung and Brown, April S. and Wang, Yongqian and Wang, Zhong L.},
Title = {Self-assembled quantum dot transformations via anion
exchange},
Journal = {Journal of Vacuum Science and Technology B: Microelectronics
and Nanometer Structures},
Volume = {19},
Number = {4},
Pages = {1463 - 1466},
Address = {Tempe, AZ, United States},
Year = {2001},
url = {http://dx.doi.org/10.1116/1.1385916},
Keywords = {Self assembly;Negative ions;Ion exchange;Annealing;Composition;Surface
treatment;Nucleation;Temperature;Morphology;},
Abstract = {Anion anneals have different effects on the quantum dot size
distributions and vertical self-assembly. Phosphorus anneal
at 300°C can enhance the uniformity of the dot size
distribution for both 2 and 3 ML multilayer structures. TEM
shows vertically aligned dots structure after annealing at
300°C and a relaxed structure after annealing at
350°C. Arsenic anneal increases the dot size, decreases
the dots density, and decreases the uniformity of quantum
dots distribution.},
Key = {02427144459}
}
@article{01376641976,
Author = {Lee, K.K. and Doolittle, W.A. and Kim, T.-H. and Brown, A.S. and May, G.S. and Stock, S.R. and Zu Rong Dai and Wang,
Z.L.},
Title = {A comparative study of surface reconstruction of wurtzite
GaN on (0 0 0 1) sapphire by RF plasma-assisted molecular
beam epitaxy},
Journal = {Journal of Crystal Growth},
Volume = {231},
Number = {1-2},
Pages = {8 - 16},
Year = {2001},
url = {http://dx.doi.org/10.1016/S0022-0248(01)01307-0},
Keywords = {Gallium nitride;Molecular beam epitaxy;Surface
structure;Sapphire;Plasma applications;Reflection high
energy electron diffraction;Transmission electron
microscopy;Hall effect;Thin films;Semiconducting
films;},
Abstract = {We present a comprehensive study of the electrical, optical,
and structural properties of wurtzite GaN films grown under
various initial growth conditions The GaN films were grown
directly on sapphire substrates using GaN nucleation layers
by a Riber 3200 system with a radio-frequency plasma source.
In situ reflection high-energy electron diffraction (RHEED)
reveals a strong correlation between nucleation conditions,
including the nitridation step, and the final surface
reconstruction of the GaN thin film. Well-defined
reconstruction patterns, primarily (2 × 2) and (4
× 4), are observed for some of the nucleation
conditions. Hall mobility, photoluminescence (PL), X-ray
rocking curve data, and transmission electron microscopy
(TEM) measurements are used to interpret the observed
relationship. The results show that for the conditions
investigated, an unreconstructed (1 × 1) surface after
growth correlates with improved electrical, optical, and
structural properties. The surface reconstructed thin film
exhibits a strong columnar growth with inversion domains
(IDs). We attribute the degraded characteristics to the
presence of a mixture of both polarities in the films with
reconstruction. © 2001 Published by Elsevier Science
B.V.},
Key = {01376641976}
}
@article{01236528551,
Author = {Kang, S. and Doolittle, W.A. and Lee, K.K. and Dai, Z.R. and Wang, Z.L. and Stock, S.R. and Brown, A.S.},
Title = {Characterization of AlGaN/GaN structures on various
substrates grown by radio frequency-plasma assisted
molecular beam epitaxy},
Journal = {Journal of Electronic Materials},
Volume = {30},
Number = {3},
Pages = {156 - 161},
Year = {2001},
Keywords = {Heterojunctions;Semiconducting aluminum compounds;Gallium
nitride;Semiconductor growth;Molecular beam epitaxy;Surface
properties;Morphology;Atomic force microscopy;Grain size and
shape;Surface roughness;Transmission electron
microscopy;Interfaces (materials);},
Abstract = {The structural properties and surface morphology of
AlGaN/GaN structures grown on LiGaO<sub>2</sub> (LGO),
sapphire, and hydride vapor phase epitaxy (HVPE)-grown GaN
templates are compared. AlGaN grown on LGO substrates shows
the narrowest x-ray full width at half maximum (FWHM) for
both symmetric less than or equal 00.4> and asymmetric
less than or equal 10.5> reflections. Atomic force
microscopy (AFM) analysis on AlGaN surfaces on LGO
substrates also show the smoothest morphology as determined
by grain size and rms roughness. The small lattice mismatch
of LGO to nitrides and easily achievable Ga-polarity of the
grown films are the primary reasons for the smoother surface
of AlGaN/GaN structure on this alternative substrate.
Optimizations of growth conditions and substrate preparation
results in step flow growth for an AlGaN/GaN structure with
300 A thick Al<sub>0.25</sub>Ga<sub>0.75</sub>N on 2.4 μm
thick GaN. A high III/V flux ratio during growth and
recently improved polishing of LGO substrates aids in
promoting two dimensional step flow growth. The GaN
nucleation layer directly on the LGO substrates showed no
evidence of mixed phase cubic and hexagonal structure that
is typically observed in the nucleation buffer on sapphire
substrates. Cross-sectional high-resolution transmission
electron microscopy (HRTEM) was performed on an AlGaN/GaN
hetero-structure grown on LGO. The atomic arrangement at the
AlGaN/GaN interface was sharp and regular, with locally
observed monolayer and bilayer steps.},
Key = {01236528551}
}
@article{01045602795,
Author = {Namkoong, Gon and Doolittle, W. Alan and Brown, April
S.},
Title = {Incorporation of Mg in GaN grown by plasma-assisted
molecular beam epitaxy},
Journal = {Applied Physics Letters},
Volume = {77},
Number = {26},
Pages = {4386 -},
Year = {2000},
url = {http://dx.doi.org/10.1063/1.1334942},
Key = {01045602795}
}
@article{00085279621,
Author = {Jokerst, Nan Marie and Brooke, Martin A. and Laskar, Joy and Wills, D. Scott and Brown, April S. and Ingram, Mary
Ann},
Title = {Building collaborative teams for multi-disciplinary
educational projects in optoelectronics},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {3831},
Pages = {25 - 35},
Address = {Cancun, Mexico},
Year = {2000},
url = {http://dx.doi.org/10.1117/12.388713},
Keywords = {Engineering education;Strategic planning;},
Abstract = {Multidisciplinary team-oriented research is an effective
method for investigating systems spanning multiple knowledge
areas. Building on cross-functional team strategies
developed for highly competitive industries, experts from a
variety of technical domains can be brought together in a
team and focused toward a common set of goals. However,
building and maintaining these teams is an art that combines
technical, social, and management skills, and requires
proactive, conscious attention to enable and achieve
positive results. This paper explores some avenues toward
effective multi-disciplinary team building, and explores the
educational potential associated with team-oriented
research. The first step in team research is to identify an
appropriate technical topic and to build a team around the
technical areas associated with that topic. Consensus
building is a key aspect to successful team research, as is
the goal that every team member achieves research sub-goals
as part of the larger effort. Team researchers optimally
have a willingness to act in a cooperative rather than
competitive fashion with team members, initially communicate
with minimal jargon, meet regularly with other team members,
share resources, and be personally responsible for their
portions of the project. Additional strategies include
recognizing and appreciating myriad levels of diversity in
the group, valuing the cross disciplinary education of team
members, inserting new technology when appropriately mature,
and setting timelines and resource allocation using a
consensus approach. Multi-disciplinary teams can address
problems which are higher in complexity than those addressed
by individuals, yet also offer the leveraging, and time and
funding buffering that is so important in shortening
research time cycles.},
Key = {00085279621}
}
@article{01045593375,
Author = {Jokerst, Nan M. and Brooke, Martin A. and Laskar, J. and Wills, D. Scott and Brown, A.S. and Vrazel, M. and Jung, S. and Joo, Y. and Chang, J.J.},
Title = {Microsystem optoelectronic integration for mixed multisignal
systems},
Journal = {IEEE Journal on Selected Topics in Quantum
Electronics},
Volume = {6},
Number = {6},
Pages = {1231 - 1239},
Year = {2000},
url = {http://dx.doi.org/10.1109/2944.902172},
Keywords = {VLSI circuits;CMOS integrated circuits;Semiconducting
gallium compounds;Semiconducting silicon;Optical
interconnects;MESFET devices;Computer networks;},
Abstract = {The integration and packaging of optoelectronic devices with
electronic circuits and systems has growing application in
many fields, ranging from long to micro haul links. An
exploration of the opportunities, integration technologies,
and some recent results using thin-film device heterogeneous
integration with Si CMOS VLSI and GaAs MESFET circuit
technologies are presented in this paper. Applications
explored herein include alignment tolerant optoelectronic
links for network interconnections, smart pixel focal plane
array processing through the integration of imaging arrays
with sigma delta analog to digital converters underneath
each pixel, and three-dimensional computational systems
using vertical through-Si optical interconnections.},
Key = {01045593375}
}
@article{00085291395,
Author = {Lee, Kyeong K. and Doolittle, William A. and Brown, April S. and May, Gary S. and Stock, Stuart R.},
Title = {Using statistical experimental design to investigate the
role of the initial growth conditions on GaN epitaxial films
grown by molecular beam epitaxy},
Journal = {Journal of Vacuum Science and Technology B: Microelectronics
and Nanometer Structures},
Volume = {18},
Number = {3},
Pages = {1448 - 1452},
Year = {2000},
url = {http://dx.doi.org/10.1116/1.591401},
Keywords = {Semiconducting gallium compounds;Film growth;Nucleation;Crystal
orientation;Substrates;Molecular beam epitaxy;Statistical
methods;Nitrogen;Hall effect;Carrier mobility;Atomic force
microscopy;Reflection high energy electron
diffraction;},
Abstract = {The initial growth stage of GaN growth directly on basal
plane sapphire substrate is investigated. Statistical
experimental design is used for the optimization of
processes with a large number of interwoven effects. The
effects of growth conditions on electrical and surface
morphology are analyzed by means of Hall mobility and atomic
force microscopy. The interactions between Ga flux and
nitrogen power during the buffer growth are
discussed.},
Key = {00085291395}
}
@article{00075228398,
Author = {Kang, Sangbeom and Doolittle, W. Alan and Stock, Stuart R. and Brown, April S.},
Title = {Comparison of AlGaN and GaN grown on various substrates:
Step flow growth on LiGaO2 at low growth
temperature},
Journal = {Materials Science Forum},
Volume = {338 (II},
Pages = {1499 - 1502},
Address = {Research Triangle Park, NC, USA},
Year = {2000},
Keywords = {Heterojunctions;Semiconducting aluminum compounds;Semiconducting
gallium compounds;Vapor phase epitaxy;Semiconductor
growth;Lithium compounds;Sapphire;Morphology;Dislocations
(crystals);Crystal symmetry;Crystal lattices;Nitrides;},
Abstract = {AlGaN/GaN heterostructures were grown on LiGaO<sub>2</sub>
(LGO), sapphire, and hydride vapor phase epitaxy (HVPE)
grown GaN substrates. Structural properties and surface
morphology of each film was compared. LGO substrates
produced the lowest FWHM values for both symmetric [Left
Angle Bracket] 00.4 [Right Angle Bracket] and asymmetric
[Left Angle Bracket] 10.5 [Right Angle Bracket] reflections.
The films grown on LGO substrate also showed the best
morphology. The small lattice mismatch of LGO to nitrides
and Ga-polarity of grown films could be the primary reason
for the smoother surface of AlGaN/GaN structure on LGO
substrates. In developing the HFET structure on the LGO
substrate, we have observed step flow growth in a structure
with 300 angstroms thick Al<sub>0.25</sub>Ga<sub>0.75</sub>N
on 2.4 µm thick GaN, which is very similar to the
films grown by MOCVD. A high III/V flux ratio during growth
and recently improved polishing of LGO substrates may have
aided in promoting two dimensional step flow
growth.},
Key = {00075228398}
}
@article{00045142146,
Author = {Kim, Tong-Ho and Brown, April S. and Metzger, Robert
A.},
Title = {Electrical properties of InAlAs/InAsxP1-x/InP
composite-channel modulation-doped structures grown by solid
source molecular beam epitaxy},
Journal = {Journal of Electronic Materials},
Volume = {29},
Number = {2},
Pages = {215 - 221},
Year = {2000},
Keywords = {Semiconducting indium phosphide;Semiconductor
doping;Molecular beam epitaxy;X ray diffraction
analysis;Semiconductor quantum wells;Carrier
mobility;Surface roughness;},
Abstract = {We report on the electrical characteristics of the
two-dimensional electron gas (2DEG) formed in an
InAlAs/InAs<sub>x</sub>P<sub>1-x</sub>/InP pseudomorphic
composite-channel modulation-doped (MD) structure grown by
solid source (arsenic and phosphorus) molecular beam epitaxy
(SSMBE). The As composition, x, of strained
InAs<sub>x</sub>P<sub>1-x</sub> was determined by x-ray
diffraction analysis of InP/InAs<sub>x</sub>P<sub>1-x</sub>/InP
multi-quantum wells (MQWs) with compositions of x = 0.14 to
x = 0.72. As the As composition increases, the room
temperature sheet resistance of InAlAs/InAs<sub>x</sub>P<sub>1-x</sub>/InP
composite-channel MD structures grown over a range of As
compositions decreased from 510 to 250 Ω/cm<sup>2</sup>,
resulting from the greater 2DEG confinement and lower
electron effective mass in the InAs<sub>x</sub>P<sub>1-x</sub>
channel as x increases. The influence of growth conditions
and epitaxial layer designs on the 2DEG mobility and
concentration were investigated using 300 K and 77 K Hall
measurements. As the exposure time of the As<sub>4</sub>
flux on the growth front of InAs<sub>x</sub>P<sub>1-x</sub>
increased during growth interruptions, the 2DEG mobility, in
particular the 77 K mobility, was considerably degraded due
to increased roughness at the InAlAs/InAs<sub>x</sub>P<sub>1-x</sub>
interface. For the InAlAs/InAs<sub>0.6</sub>P<sub>0.4</sub>/InP
composite-channel MD structure with a spacer thickness of 8
nm, the room temperature 2DEG mobility and density were 7200
cm<sup>2</sup>/Vs and 2.5×10<sup>12</sup>
cm<sup>-2</sup>, respectively. These results show the great
potential of the InAlAs/InAs<sub>x</sub>P<sub>1-x</sub>/InP
pseudomorphic composite-channel MD heterostructure for high
frequency, power device applications.},
Key = {00045142146}
}
@article{6869462,
Author = {Gon Namkoong and Doolittle, W.A. and Sangbeom Kang and Huang
Sa and Brown, A.S. and Stock, S.R.},
Title = {Low temperature nitridation combined with high temperature
buffer annealing for high quality GaN grown by
plasma-assisted MBE},
Journal = {MRS Internet J. Nitride Semicond. Res. (USA)},
Volume = {5S1},
Year = {2000},
Keywords = {annealing;gallium compounds;grain size;III-V
semiconductors;molecular beam epitaxial growth;nitridation;plasma
deposition;wide band gap semiconductors;},
Abstract = {The effect of the initial nitridation of the sapphire
substrate on the GaN crystal quality as a function of
substrate temperature was studied. GaN layers were grown by
plasma-assisted molecular beam epitaxy (MBE) on sapphire
substrates nitridated at different substrate temperatures. A
strong improvement in the GaN crystal quality was observed
at 100°C nitridation temperature. Symmetric (0004) and
asymmetric (10-5) full widths at half maximum (FWHM) of the
X-ray rocking curves were 136 and 261 arcsec, respectively.
This compares to an X-ray rocking curve full width at half
maximum of 818 arcsec (0004) for conventional MBE buffer
conditions. For our conventional buffer conditions, sapphire
substrates were exposed to a N plasma at temperatures above
500°C for 10 min and then 25-50 nm buffers were
deposited without annealing at high temperature. The low
temperature nitridation also shows an enhancement of the
lateral growth of the GaN, resulting in larger grain sizes.
The largest grain size achieved was approximately 2.8 μm,
while the average grain size was approximately 2.4 μm at
100°C nitridation temperature},
Key = {6869462}
}
@article{00115391371,
Author = {Brown, April S. and Doolittle, W. Alan},
Title = {Status and promise of compliant substrate
technology},
Journal = {Applied Surface Science},
Volume = {166},
Number = {1},
Pages = {392 - 398},
Year = {2000},
url = {http://dx.doi.org/10.1016/S0169-4332(00)00455-4},
Keywords = {Semiconducting glass;Semiconducting gallium
compounds;Semiconductor growth;Chemical bonds;},
Abstract = {Compliant substrates offer significant promise as a new
approach for strain management in semiconductors. The
primary application is to produce device-quality highly
mismatched materials on dissimilar substrates. Various
implementations and processes for achieving substrate
compliancy have been proposed and demonstrated. These
include the use of twist-, glass-, and metal-bonds, and the
use of engineered templates realized with laterally oxidized
Al-containing alloys. A recent focus in our work has been on
the growth of GaN on a novel and easily removable substrate
- lithium gallate - for regrowth on a bonded GaN
template.},
Key = {00115391371}
}
@article{00085299636,
Author = {Brown, April S. and Doolittle, W. Alan and Kang, Sangbeom and Shen, Jeng-Jung and Wang, Z.L. and Dai,
Z.},
Title = {Growth of GaN on lithium gallate (LiGaO2)
substrates for material integration},
Journal = {Journal of Electronic Materials},
Volume = {29},
Number = {7},
Pages = {894 - 896},
Address = {Lake Buena Vista, FL, USA},
Year = {2000},
Keywords = {Semiconductor growth;Lithium compounds;Substrates;Strain;Bonding;Thermal
stress;Relaxation processes;Dissimilar materials;Crystal
lattices;},
Abstract = {Compliant substrates offer a new approach for strain
management in semiconductors. Various implementations and
processes for achieving substrate compliancy have been
proposed and demonstrated. These include the use of twist-,
glass-, and metal-bonds. A recent focus in our work has been
on the growth of GaN on a novel and easily removable
substrate-lithium gallate-for the ultimate regrowth on a
bonded GaN template. The bonding technology is important to
reduce thermal stresses during the regrowth step. Herein, we
focus on the understanding of the growth of GaN on lithium
gallate.},
Key = {00085299636}
}
@article{6986282,
Author = {Jokerst, N. and Brooke, M.A. and Laskar, J. and Wills, D. and Brown, A.S. and Vendier, O. and Bond, S.W. and Cross,
J.B. and Vrazel, M. and Thomas, M. and Lee, M. and Jung, S. and Joo, Y. and Chang, J.J.},
Title = {Smart photonics: optoelectronics integrated with Si CMOS
VLSI circuits},
Journal = {Proc. SPIE - Int. Soc. Opt. Eng. (USA)},
Volume = {4109},
Pages = {241 - 51},
Address = {San Diego, CA, USA},
Year = {2000},
Keywords = {integrated logic circuits;integrated optics;integrated
optoelectronics;optoelectronic devices;},
Abstract = {Smart photonics, the integration of optoelectronic devices
with electronic circuits and systems, has growing
applications in many fields, one of which is computing. An
exploration of the opportunities, integration technologies,
and some recent results using thin film optoelectronic and
electronic device integration with Si CMOS VLSI and GaAs
MESFET technologies are presented herein. Applications
explored herein include low cost alignment tolerant
optoelectronic interconnection links for network
interconnections, smart focal plane array processing through
the integration of imaging arrays with sigma delta analog to
digital converters underneath each pixel, and three
dimensional computational systems using vertical through-Si
optical interconnections},
Key = {6986282}
}
@article{01506759453,
Author = {Shen, J.-J. and Kim, T.-H. and Brown, A.S.},
Title = {Growth and characterization of InGaAs/AlInAs HEMT structures
on oxide-bonded InGaAs substrates},
Journal = {IEEE International Symposium on Compound Semiconductors,
Proceedings},
Pages = {131 - 135},
Address = {Monterey, CA},
Year = {2000},
url = {http://dx.doi.org/10.1109/ISCS.2000.947142},
Keywords = {High electron mobility transistors;Semiconducting indium
gallium arsenide;Electric properties;Electron
mobility;Morphology;Lattice constants;X ray
analysis;},
Abstract = {InGaAs/AlInAs HEMT structures have been grown on
oxide-bonded InGaAs substrates. De-oxidation and growth
conditions are developed that enable good electrical
properties. The highest electron mobility obtained was 7258
cm<sup>2</sup>/V at 300K. The surface morphology showed
undulations. X-ray rocking curve analysis shows differences
in lattice constants between the samples grown on control
substrates and the oxide-bonded substrates.},
Key = {01506759453}
}
@article{99094798346,
Author = {Matyi, R.J. and Doolittle, W.A. and Brown,
A.S.},
Title = {High resolution X-ray diffraction analyses of
GaN/LiGaO2},
Journal = {Journal of Physics D: Applied Physics},
Volume = {32},
Number = {10A},
Pages = {61-64 -},
Address = {Durham, UK},
Year = {1999},
url = {http://dx.doi.org/10.1088/0022-3727/32/10A/313},
Keywords = {Semiconducting gallium compounds;Lithium compounds;Molecular
beam epitaxy;Epitaxial growth;Crystal structure;Temperature;},
Abstract = {Lithium gallate (LiGaO<sub>2</sub>) is gaining increasing
attention as a potential substrate for the growth of the
important semiconductor GaN. In order to better understand
this material we have performed high-resolution double- and
triple-axis x-ray diffraction analyses of both the starting
LiGaO<sub>2</sub> and GaN/LiGaO<sub>2</sub> following
epitaxial growth. A high-resolution triple-axis reciprocal
space map of the substrate showed a sharp, well-defined
crystal truncation rod and a symmetric streak of intensity
perpendicular to q<sub>002</sub>, suggesting high structural
quality with mosaic spread. Triple-axis scans following GaN
growth showed (1) the development of isotropic diffuse
scatter around the LiGaO<sub>2</sub> (002) reflection, (2)
the presence of a semi-continuous intensity streak between
the LiGaO<sub>2</sub> (002) and GaN (0002) reflections, and
(3) a compact pattern of diffuse scatter around the GaN
(0002) reflection that becomes increasingly anisotropic as
the growth temperature is increased. These results suggest
that LiGaO<sub>2</sub> permits the epitaxial growth of GaN
with structural quality that may be superior to that
observed when growth is performed on SiC or
Al<sub>2</sub>O<sub>3</sub>.},
Key = {99094798346}
}
@article{99104871880,
Author = {Kim, T.-H. and Brown, A.S. and Metzger, R.A.},
Title = {Optical and structural properties of strained
InAlAs/InAsxP1-x multi-quantum wells
grown by solid source molecular beam epitaxy},
Journal = {Journal of Applied Physics},
Volume = {86},
Number = {5},
Pages = {2622 - 2627},
Year = {1999},
url = {http://dx.doi.org/10.1063/1.371101},
Keywords = {Heterojunctions;Semiconducting indium phosphide;Photoluminescence;Molecular
beam epitaxy;Strain;X ray crystallography;Semiconductor
growth;},
Abstract = {The growth of InP/InAs<sub>x</sub>P<sub>1-x</sub> and
InAlAs/InAs<sub>x</sub>P<sub>1-x</sub> heterostructures was
studied using P and As sources. The As<sub>4</sub> flux is
incorporated much less efficiently into higher As percentage
InAsP due to the higher strain in the grown InAsP film. The
InP/InAsP multiple quantum wells showed photoluminescence at
full width at half maximums of 12-19 meV at 4.2
K.},
Key = {99104871880}
}
@article{99124946441,
Author = {Dagnall, G. and Brown, A.S. and Stock, S.R.},
Title = {Arsenic incorporation in InAsP/InP quantum
wells},
Journal = {Journal of Electronic Materials},
Volume = {28},
Number = {10},
Pages = {1108 - 1110},
Year = {1999},
Keywords = {Semiconducting indium phosphide;Arsenic;Molecular beam
epitaxy;Semiconductor growth;},
Abstract = {InAsP/InP multiquantum well structures were grown by solid
source molecular beam epitaxy using either As<sub>2</sub> or
As<sub>4</sub> over a substrate temperature range of 420-535
°C. All quantum wells had similar arsenic compositions
with a 2.2% standard deviation regardless of arsenic species
or growth temperature. This temperature insensitivity of
arsenic incorporation in InAsP is in sharp contrast to
InGaAsP in which arsenic composition is very sensitive to
both substrate temperature and gallium percentage in the
compound. The insensitivity of arsenic incorporation in
InAsP to substrate temperature may result from growth in a
phosphorus rich condition with indium as the only available
cation.},
Key = {99124946441}
}
@article{99124935595,
Author = {Dagnall, Georgiana and Shen, Jeng-Jung and Kim, Tong-Ho and Metzger, Robert A. and Brown, April S. and Stock, Stuart
R.},
Title = {Solid source MBE growth of InAsP/InP quantum
wells},
Journal = {Journal of Electronic Materials},
Volume = {28},
Number = {8},
Pages = {933 - 938},
Year = {1999},
Keywords = {Semiconducting indium compounds;Molecular beam
epitaxy;Substrates;Crystal structure;Dimers;Temperature;X
ray diffraction analysis;Arsenic;Photoluminescence;Surface
roughness;Atomic force microscopy;},
Abstract = {Strained InAsP multiquantum wells (MWQs) were grown on
InP(100) substrates by solid source molecular beam epitaxy
and were characterized to relate structural and optical
quality to growth conditions. The multiquantum wells were
grown using either dimer or tetramer arsenic (As<sub>2</sub>
or As<sub>4</sub>) over the substrate temperature range of
420-535°C. θ-2θ x-ray diffraction
measurements showed only slight differences between arsenic
compositions in the quantum wells grown with As<sub>2</sub>
or As<sub>4</sub>. 300K and 8K photoluminescence full width
at half max (FWHM) decreased at higher growth temperatures
regardless of the arsenic species used. The 8K
photoluminescence FWHM and the surface roughness measured by
atomic force microscopy are found to be less sensitive to
substrate growth temperature for the multiquantum wells
growth with As<sub>2</sub> as opposed to
As<sub>4</sub>.},
Key = {99124935595}
}
@article{00024997668,
Author = {Doolittle, W.A. and Brown, A.S.},
Title = {Compliant substrate processes},
Journal = {Materials Research Society Symposium - Proceedings},
Volume = {570},
Pages = {225 - 234},
Address = {San Frnacisco, CA, USA},
Year = {1999},
Keywords = {Substrates;Dissimilar materials;Semiconductor growth;Band
structure;Strain rate;Semiconductor device
manufacture;Epitaxial growth;Crystal defects;Thermal
expansion;Transmission electron microscopy;X ray diffraction
analysis;},
Abstract = {Recent results indicate that compliant substrates offer
significant promise as a new approach for strain management
in semiconductors. The potential applications include 1) the
growth of device-quality highly mismatched materials on
dissimilar substrates, and 2) the lateral control of
material properties resulting from the effects of strain on
bandstructure and/or growth dynamics. A significant amount
of research in this area is dedicated to the reduction of
extrinsic processing effects resulting from compliant
substrate fabrication, and the development of simple models
for understanding the observed reduction in defect density
and/or strain in the epitaxial films grown on compliant
substrates. A recent focus in our work has been on the
growth of GaN on a novel and easily removable substrate -
lithium gallate- for the regrowth on a bonded GaN template.
The first step in this approach is the optimization of the
growth of GaN on lithium gallate. In addition, this approach
requires the use of an appropriate bonding layer to reduce
the strain or defect production during growth due to
coefficient of thermal expansion mismatches between the GaN
sample and the handle wafer. Our work in this area will be
highlighted in the context of an overview of various
compliant substrate approaches and current results that
indicate their efficacy.},
Key = {00024997668}
}
@article{99084751765,
Author = {Dagnall, G. and Stock, S.R. and Brown, A.S.},
Title = {Growth of InAsP/InP quantum wells by solid source MBE on
misoriented and exact InP (1 1 1)B: Substrate temperature
and arsenic species effects},
Journal = {Journal of Crystal Growth},
Volume = {201-202},
Pages = {242 - 247},
Address = {Cannes},
Year = {1999},
url = {http://dx.doi.org/10.1016/S0022-0248(98)01330-X},
Keywords = {Semiconductor quantum wells;Semiconducting indium
phosphide;Molecular beam epitaxy;Substrates;Crystal
orientation;X ray diffraction analysis;Atomic force
microscopy;Photoluminescence;},
Abstract = {Two series of strained InAsP/InP multiquantum wells (MQWs)
were grown by solid source molecular beam epitaxy (SSMBE)
simultaneously on Fe-doped InP substrates with a growth
orientation of either (1 0 0), exact (1 1 1)B, and (1 1 1)B
misoriented 1° toward [Left Angle Bracket] -2 1 1 [Right
Angle Bracket] . The MQWs were grown using either dimer or
tetramer arsenic (As<sub>2</sub> or As<sub>4</sub>) over a
substrate temperature range of 420-535 °C. The
θ-2θ X-ray diffraction measurements, the atomic
force microscopy (AFM) images of the surfaces, and the 8 K
photoluminescence (PL) full-width at half-maximum (FWHM)
values of the (1 1 1)B samples showed general improvement in
the samples' material properties with increasing substrate
temperature. While the X-ray diffraction measurements and
the AFM images showed little difference between
As<sub>2</sub> and As<sub>4</sub>, the 8 K PL FWHM values
varied greatly with respect to the arsenic species used. The
exact (1 1 1)B samples had narrower 8 K PL FWHM values when
grown with As<sub>2</sub>. For growth on misoriented (1 1
1)B InP, the 8 K FWHM values narrowed with As<sub>4</sub>.
The misoriented (1 1 1)B samples had the narrowest 8 K PL
FWHM when grown with As<sub>4</sub> at a temperature of 520
°C; the exact (1 1 1)B at 495 °C when grown with
As<sub>2</sub>.},
Key = {99084751765}
}
@article{04057901360,
Author = {Kang, Sangbeom and Doolittle, William A. and Brown, April S. and Stock, Stuart R.},
Title = {Electrical and structural characterization of
AlxGa1-xN/GaN heterostructures grown
on LiGaO2 substrates},
Journal = {Applied Physics Letters},
Volume = {74},
Number = {22},
Pages = {3380 - 3382},
Year = {1999},
url = {http://dx.doi.org/10.1063/1.123351},
Abstract = {In this letter, we report on the properties of a
Al<sub>x</sub>Ga<sup>1-x</sup>N/GaN heterostructure grown on
LiGaO<sub>2</sub>. A two-dimensional electron gas (2DEG) is
observed with mobility of 731 cm<sup>2</sup>/V s at room
temperature and 2166 cm<sup>2</sup>/V s at 77 K. A
comparison of the structural quality of the heterostructure
as determined by x-ray diffraction shows significant
improvement in comparison to a similar structure grown on a
sapphire substrate. Secondary ion mass spectroscopy analysis
indicates that lithium diffuses into the GaN during growth.
The concentration decreases by two orders of magnitude from
the substrate to the surface in a 0.8 μm thick GaN film.
The enhancement of the mobility of the 2DEG compared to that
of electrons in a uniformly doped film is due, in part, to
the proximity of the 2DEG to the film surface, where the Li
concentration is lower. In addition, we believe that the
surface roughness plays a role in the mobility of the 2DEG.
Despite these extrinsic factors, the good conductivity of
the 2DEG shows the promise of LiGaO<sub>2</sub> as a
substrate for device-quality GaN. © 1999 American
Institute of Physics.},
Key = {04057901360}
}
@article{00025003964,
Author = {Jokerst, Nan Marie and Brooke, Martin A. and Laskar, Joy and Wills, D. Scott and Brown, April S. and Vendier, Olivier and Bond, Steven and Cross, Jeffrey and Vrazel, Michael and Thomas, Mikkel and Lee, Myunghee and Jung, Sungyung and Joo,
Yoong Joon and Chang, Jae Joon},
Title = {Smart photonics: Optoelectronics integrated onto Si CMOS
circuits},
Journal = {Conference Proceedings - Lasers and Electro-Optics Society
Annual Meeting-LEOS},
Volume = {2},
Pages = {423 - 424},
Address = {San Francisco, CA, USA},
Year = {1999},
url = {http://dx.doi.org/10.1109/LEOS.1999.811779},
Keywords = {Silicon wafers;Thin film circuits;CMOS integrated
circuits;VLSI circuits;Optical links;Optical
interconnects;Electronics packaging;},
Abstract = {Smart photonics, or the integration of optoelectronic (OE)
devices and links with circuitry such as Si complementary
metal oxide semiconductor (CMOS) very large scale integrated
(VLSI) circuits, can yield both advanced optical links and
possibly integrated solutions for optoelectronic interfaces
and interconnections to standard electronic systems. Coupled
with alignment tolerant designs, these implementations may
yield cost effective solutions which are compatible and
integrable with electronic systems. The options in stacking
of thin films circuit or in the vertical optical
interconnection of Si CMOS circuits using through-Si optical
signals are explored in the context of hybrid thin film
integration and packaging.},
Key = {00025003964}
}
@article{98054210657,
Author = {Kropewnicki, Thomas J. and Doolittle, W. Alan and Carter-Coman, Carrie and Kang, Sangboem and Kohl, Paul A. and Jokerst, Nan Marie and Brown, April S.},
Title = {Selective wet etching of lithium gallate},
Journal = {Journal of the Electrochemical Society},
Volume = {145},
Number = {5},
Pages = {88-90 -},
Year = {1998},
Keywords = {Etching;Crystal lattices;Semiconductor growth;Substrates;Thin
films;Film growth;Semiconducting films;},
Abstract = {Lithium gallate (LGO) is an attractive, near lattice matched
substrate for the growth of GaN. In addition, LGO substrates
provide a convenient route to forming thin films of GaN as
used in substrate removal or lift-off processes. We report
the wet etching of LGO substrates for the production of GaN
thin films. Two face-selective LGO etches have been used for
the processing of substrates. The etch rate of the cation
face is reported here for the first time and is 0.25 μm
min<sup>-1</sup> at 50 °C. The etching solution is safe
and benign to most materials including metallic
bonding.},
Key = {98054210657}
}
@article{99024581247,
Author = {Shen, Jeng-Jung and Jokerst, Nan Marie and Brown, April
S.},
Title = {Compliant substrate strain modulated epitaxy for WDM laser
arrays},
Journal = {Conference Proceedings - Lasers and Electro-Optics Society
Annual Meeting-LEOS},
Volume = {1},
Pages = {95 - 96},
Address = {Orlando, FL, USA},
Year = {1998},
Keywords = {Wavelength division multiplexing;Epitaxial
growth;Mathematical models;Substrates;Energy
gap;Strain;Semiconductor device manufacture;},
Abstract = {A new method for making a multiple-wavelength laser array by
using strain modulated epitaxy is described. This growth
process, which enables growth on a smooth substrate surface
while enabling three dimensional band structure engineering,
uses a bottom-patterned compliant substrate to modulate the
strain variation on the epitaxial layer grown on the
compliant substrate. To achieve the strain variation as a
function of lateral position on the grown sample, a bottom
patterned compliant substrate is used to vary the strain. A
mathematical model has been developed for the realization of
a multiple wavelength laser array using bottom patterned
compliant substrates.},
Key = {99024581247}
}
@article{98094378442,
Author = {Brown, April S.},
Title = {Compliant substrate technology: status and
prospects},
Journal = {Journal of Vacuum Science & Technology B: Microelectronics
Processing and Phenomena},
Volume = {16},
Number = {4},
Pages = {2308 -},
Year = {1998},
url = {http://dx.doi.org/10.1116/1.590166},
Key = {98094378442}
}
@article{98074283107,
Author = {Shen, Jeng-Jung and Brown, April S. and Metzger, Robert A. and Sievers, Barry and Bottomley, Lawrence and Eckert,
Patrick and Carter, W. Brent},
Title = {Modification of quantum dot properties via surface exchange
and annealing: substrate temperature effects},
Journal = {Journal of Vacuum Science & Technology B: Microelectronics
Processing and Phenomena},
Volume = {16},
Number = {3},
Pages = {1326 -},
Year = {1998},
url = {http://dx.doi.org/10.1116/1.590068},
Key = {98074283107}
}
@article{98074283101,
Author = {Doolittle, William A. and Kropewnicki, Tom and Carter-Coman,
C. and Stock, S. and Kohl, Paul and Jokerst, Nan Marie and Metzger, Robert A. and Kang, Sangbeom and Lee, Kyeong Kyun and May, Gary and Brown, April S.},
Title = {Growth of GaN on lithium gallate substrates for development
of a GaN thin compliant substrate},
Journal = {Journal of Vacuum Science & Technology B: Microelectronics
Processing and Phenomena},
Volume = {16},
Number = {3},
Pages = {1300 -},
Year = {1998},
url = {http://dx.doi.org/10.1116/1.590005},
Key = {98074283101}
}
@article{6118067,
Author = {Doolittle, W.A. and Kropewnicki, T. and Carter-Coman, C. and Stock, S. and Kohl, P. and Jokerst, N.M. and Metzger, R.A. and Kang, S. and Lee, K. and May, G. and Brown,
A.S.},
Title = {Growth of GaN on lithium gallate substrates for development
of a GaN thin compliant substrate},
Journal = {Nitride Semiconductors Symposium},
Pages = {283 - 8},
Address = {Boston, MA, USA},
Year = {1998},
Keywords = {doping profiles;electron mobility;gallium compounds;III-V
semiconductors;molecular beam epitaxial growth;semiconductor
epitaxial layers;semiconductor growth;surface
structure;thermal conductivity;thermally stimulated
desorption;wide band gap semiconductors;X-ray
diffraction;X-ray photoelectron spectra;},
Abstract = {The GaN on LGO system is the near perfect template (due to
extremely high etch selectivity) for developing a viable
thin film/compliant GaN substrate. Herein, we report on our
efforts to grow GaN on LGO, including improvement of the
microscopic surface morphology using pre-growth
pretreatments. We also report on the first transferred thin
film GaN substrate grown on LGO, transferred off of LGO, and
mounted on GaAs. With this approach, (InAl)GaN alloys can be
grown on thin GaN films, implementing a truly
“compliant” substrate for the nitride alloy
system. In addition, the flexibility of bonding to low cost
Si, metal or standard ceramic IC packages is an attractive
alternative to SiC and HVPE GaN substrates for optimizing
cost verses thermal conductivity concerns. We have
demonstrated high quality growth of GaN on LGO. X-ray
rocking curves of 145 arc-seconds are obtained with only a
0.28 μm thick film. We present data on the out of plane
crystalline quality of GaN/LGO material. Likewise, we show 2
orders of magnitude improvement in residual doping
concentration and factors of 4 improvement in electron
mobility as compared to the only previously reported
electrical data. We show substantial vendor to vendor and
intra-vendor LGO material quality variations. We have also
quantified the desorption of Ga and Li from the surface of
LGO at typical growth temperatures using in situ desorption
mass spectroscopy and XPS},
Key = {6118067}
}
@article{6051166,
Author = {Doolittle, W.A. and Kang, S. and Kropewnicki, T.J. and Stock, S. and Kohl, P.A. and Brown, A.S.},
Title = {MBE growth of high quality GaN on LiGaO2},
Journal = {J. Electron. Mater. (USA)},
Volume = {27},
Number = {8},
Pages = {58 - 60},
Year = {1998},
Keywords = {crystal structure;electron mobility;gallium compounds;III-V
semiconductors;lithium compounds;molecular beam epitaxial
growth;reflection high energy electron diffraction;semiconductor
epitaxial layers;semiconductor growth;wide band gap
semiconductors;},
Abstract = {We report on the growth of high structural quality (as
determined by X-ray diffraction) GaN on a near lattice
matched substrate, lithium gallate (LiGaO<sub>2</sub> or
LGO). Low temperature growth conditions are described that
result in very thin GaN films (<0.3 μm) with (0004)
X-ray diffraction rocking curves full width at half maximum
(FWHM) of 145 arc-sec and thicker films (1 μm) resulting
in 85 arcsec FWHM. The effect of growth temperature is
examined and found to result in a broad minimum in X-ray
FWHM around 690°C. Detailed growth conditions and
descriptions of the reflection high energy electron
diffraction patterns observed during growth are given.
Additionally, we report very highly resistive material and
doped material with bulk electron mobilities in excess of
100 cm<sup>2</sup>/V-sec},
Key = {6051166}
}
@article{97093808201,
Author = {Carter-Coman, Carrie and Bicknell-Tassius, Robert and Brown,
April S. and Jokerst, Nan Marie},
Title = {Compliant substrates for reduction of strain relief in
mismatched overlayers},
Journal = {Materials Research Society Symposium - Proceedings},
Volume = {441},
Pages = {361 - 366},
Address = {Boston, MA, USA},
Year = {1997},
Keywords = {Thin films;Mathematical models;Strain;Semiconducting indium
compounds;Semiconducting gallium arsenide;Thickness
measurement;Stress relief;},
Abstract = {Thin film compliant substrates can be used to extend the
critical thickness in mismatched overlayers. A metastability
model has been coupled with recent experimental strain
relief data to determine the critical thickness of InGaAs
epilayers grown on GaAs compliant substrates of variable
thickness. The results of this model are also compared to
other compliant substrate critical thickness
models.},
Key = {97093808201}
}
@article{97033577369,
Author = {Carter-Coman, Carrie and Bicknell-Tassius, Robert and Benz,
Rudolph G. and Brown, April S. and Jokerst, Nan
Marie},
Title = {Analysis of GaAs substrate removal etching with citric
acid:H2O2 and NH4OH:H2O2
for application to compliant substrates},
Journal = {Journal of the Electrochemical Society},
Volume = {144},
Number = {2},
Pages = {29-31 -},
Year = {1997},
Keywords = {Semiconducting gallium arsenide;Substrates;Removal;Thin
films;Acids;Semiconducting aluminum compounds;Refractive
index;},
Abstract = {New properties associated with selective substrate removal
have been observed in the application of this technique to
GaAs thin film compliant substrates. Citric acid-and
NH<sub>4</sub>OH-based etches are used to selectively etch
the GaAs substrate and stop on an AlAs layer. The AlAs
stop-etch layer is transformed into a layer that is almost
twice as thick as the original layer, mismatched to the
remaining GaAs epilayer, and has a refractive index around
2.0. Replacement of the single AlAs stop etch layer with
multiple thin AlGaAs stop etch layers is proposed to
alleviate this problem.},
Key = {97033577369}
}
@article{97083782542,
Author = {Kromann, R.F. and Bicknell-Tassius, R.N. and Brown, A.S. and Dorsey, J.F. and Lee, K. and May, G.},
Title = {Real-time monitoring of RHEED using machine vision
techniques},
Journal = {Journal of Crystal Growth},
Volume = {175-176},
Number = {pt 1},
Pages = {334 - 339},
Address = {Malibu, CA, USA},
Year = {1997},
url = {http://dx.doi.org/10.1016/S0022-0248(96)01184-0},
Keywords = {Semiconductor growth;Reflection high energy electron
diffraction;Real time systems;Digital signal
processing;Computer vision;Computer software;Computer
hardware;Spurious signal noise;Substrates;Semiconductor
quantum wells;Semiconducting gallium arsenide;Semiconductor
device structures;},
Abstract = {A RHEED system has been developed that allows real-time
monitoring of RHEED information throughout a multilayer
growth run with rotation. The machine vision system consists
of high-speed image capture hardware coupled with digital
signal processing software that allows the real-time
extraction/analysis of the RHEED intensity and width signals
from the noise induced by substrate rotation. This system
has been used to investigate the oxide desorption process on
GaAs substrates, along with the specular spot intensity and
width variation during the growth of a set of InGaAs/AlGaAs
single quantum well structures with systematically varied
process parameters. A strong correlation of the specular
spot intensity with growth parameters has been observed. It
is also shown that the observed specular spot intensity can
be used to predict the quality of the InGaAs quantum well
structures.},
Key = {97083782542}
}
@article{97103852384,
Author = {Carter-Coman, Carrie and Bicknell-Tassius, Robert and Brown,
April S. and Jokerst, Nan Marie},
Title = {Metastability modeling of compliant substrate critical
thickness using experimental strain relief
data},
Journal = {Applied Physics Letters},
Volume = {71},
Number = {10},
Pages = {1344 -},
Year = {1997},
url = {http://dx.doi.org/10.1063/1.119889},
Key = {97103852384}
}
@article{97123959032,
Author = {Carter-Coman, Carrie and Brown, April S. and Metzger, Robert
A. and Jokerst, Nan Marie and Pickering, Jason and Bottomley, Lawrence A.},
Title = {New mechanism for spontaneous nanostructure formation on
bottom-patterned compliant substrates},
Journal = {Applied Physics Letters},
Volume = {71},
Number = {19},
Pages = {2773 -},
Year = {1997},
url = {http://dx.doi.org/10.1063/1.120129},
Key = {97123959032}
}
@article{5774401,
Author = {Carter-Coman, C. and Bicknell-Tassius, R. and Brown, A.S. and Jokerst, N.M.},
Title = {Compliant substrates for reduction of strain relief in
mismatched overlayers},
Journal = {Thin Films - Structure and Morphology. Symposium},
Pages = {361 - 6},
Address = {Boston, MA, USA},
Year = {1997},
Keywords = {deformation;gallium arsenide;III-V semiconductors;indium
compounds;interface phenomena;internal stresses;semiconductor
epitaxial layers;substrates;},
Abstract = {Thin film compliant substrates can be used to extend the
critical thickness in mismatched overlayers. A metastability
model has been coupled with recent experimental strain
relief data to determine the critical thickness of InGaAs
epilayers grown on GaAs compliant substrates of variable
thickness. The results of this model are also compared to
other compliant substrate critical thickness
models},
Key = {5774401}
}
@article{98064238354,
Author = {Doolittle, W.A. and Kropewnicki, T. and Carter-Coman, C. and Stock, S. and Kohl, P. and Jokerst, N.M. and Metzger, R.A. and Kang, S. and Lee, K. and May, G. and Brown,
A.S.},
Title = {Growth of GaN on lithium gallate substrates for development
of a GaN thin compliant substrate},
Journal = {Materials Research Society Symposium - Proceedings},
Volume = {482},
Pages = {283 - 288},
Address = {Boston, MA, USA},
Year = {1997},
Keywords = {Semiconductor growth;Substrates;Thin films;Morphology;Semiconductor
doping;Desorption;Mass spectrometry;X ray photoelectron
spectroscopy;Semiconducting films;Nitrides;},
Abstract = {The GaN on LGO system is the near perfect template (due to
extremely high etch selectivity) for developing a viable
thin film/compliant GaN substrate. Herein, we report on our
efforts to grow GaN on LGO, including improvement of the
microscopic surface morphology using pre-growth
pretreatments. We also report on the first transferred thin
film GaN substrate grown on LGO, transferred off of LOG, and
mounted on GaAs. With this approach, (InAl)GaN alloys can be
grown on thin GaN films, implementing a truly `compliant'
substrate for the nitride alloy system. In addition, the
flexibility of bonding to low cost Si, metal or standard
ceramic IC packages is an attractive alternative to SiC and
HVPE GaN substrates for optimizing cost verses thermal
conductivity concerns. We have demonstrated high quality
growth of GaN on LGO. X-Ray rocking curves of 145
arc-seconds are obtained with only a 0.28 µm thick
film. We present data on the out of plane crystalline
quality of GaN/LGO material. Likewise, we show 2 orders of
magnitude improvement in residual doping concentration and
factors of 4 improvement in electron mobility as compared to
the only previously reported electrical data. We show
substantial vendor to vendor and intra-vendor LGO material
quality variations. We have also quantified the desorption
of Ga and Li from the surface of LGO at typical growth
temperatures using in situ desorption mass spectroscopy and
XPS.},
Key = {98064238354}
}
@article{97083782684,
Author = {Bicknell-Tassius, Robert N. and Lee, Kyeong and Brown, April
S. and Dagnall, Georgianna and May, Gary},
Title = {Growth of AlGaAs-InGaAs quantum-well structures by molecular
beam epitaxy: Observation of critical interdependent effects
utilizing the design of experiments approach},
Journal = {Journal of Crystal Growth},
Volume = {175-176},
Number = {pt 2},
Pages = {1131 - 1137},
Address = {Malibu, CA, USA},
Year = {1997},
url = {http://dx.doi.org/10.1016/S0022-0248(96)01210-9},
Keywords = {Semiconducting aluminum compounds;Semiconducting indium
compounds;Molecular beam epitaxy;Semiconductor
growth;Statistical methods;Semiconducting gallium
arsenide;Semiconductor device structures;},
Abstract = {The traditional approach to determine relationships between
growth conditions and material properties has rested on the
standard experimental approach - varying one parameter while
holding all others constant. This technique does not
effectively allow the observation of important interactions
in complicated multilayer structures. Critical
interdependent effects have been observed in the growth of
AlGaAs/InGaAs quantum-well structures by molecular beam
epitaxy (MBE). It is shown that statistical experimental
design is an effective method for optimizing complex
multilayer structures quickly. This technique is very useful
for the optimization of processes with a large number of
interdependent parameters and allows for the clear
visualization and separation of complex interwoven effects.
In the present work, we show for the first time the
importance of the oxide desorption process for the optimal
growth of AlGaAs-containing structures. The choice of an
optimized oxide desorption process can lead to a decrease in
the interfacial oxygen by almost two orders of
magnitude.},
Key = {97083782684}
}
@article{97083782520,
Author = {Fournier, Francoise and Metzger, Robert A. and Doolittle,
Alan and Brown, April S. and Carter-Coman, Carrie and Jokerst, Nan Marie and Bicknell-Tassius,
Robert},
Title = {Growth dynamics of InGaAs/GaAs by MBE},
Journal = {Journal of Crystal Growth},
Volume = {175-176},
Number = {pt 1},
Pages = {203 - 210},
Address = {Malibu, CA, USA},
Year = {1997},
url = {http://dx.doi.org/10.1016/S0022-0248(96)00888-3},
Keywords = {Semiconducting gallium arsenide;Semiconducting indium
compounds;Semiconductor growth;Molecular beam epitaxy;Mass
spectrometry;Activation energy;Thermal effects;Composition
effects;Arsenic;Desorption;},
Abstract = {The growth dynamics of the InGaAs/GaAs system have been
investigated by desorption mass spectrometry (DMS). Indium
desorption spectra indicate the presence of one or two
desorption mechanisms depending on the V/III beam equivalent
pressure ratio. The activation energy associated with one of
the desorption processes is found to be 1.3 eV and
independent of V/III ratio and arsenic species. Analysis of
the decay curve allows the calculation of the indium surface
population during growth. This population is compared for
the different growth conditions investigated. Indium
incorporation coefficient curves as a function of substrate
temperature are presented. Indium incorporation is found to
be enhanced using high V/III ratio and the arsenic dimer,
As<sub>2</sub>.},
Key = {97083782520}
}
@article{97053635881,
Author = {Carter-Coman, Carrie and Bicknell-Tassius, Robert and Brown,
April S. and Jokerst, Nan Marie},
Title = {Analysis of In0.07Ga0.93As layers on
GaAs compliant substrates by double crystal x-ray
diffraction},
Journal = {Applied Physics Letters},
Volume = {70},
Number = {13},
Pages = {1754 - 1756},
Year = {1997},
url = {http://dx.doi.org/10.1063/1.118647},
Keywords = {X ray crystallography;Semiconducting gallium
arsenide;Crystal growth;Thin films;Bonding;Strain;Lattice
constants;Calculations;Crystal defects;},
Abstract = {Five consecutive InGaAs-GaAs growths are conducted
simultaneously on GaAs-based thin film compliant substrates
and thick reference substrates using double crystal x-ray
diffraction. The In<sub>0.07</sub>Ga<sub>0.93</sub>As layers
are grown to thicknesses below and above the conventional
critical thickness. It is found that InGaAs films grown on
the compliant substrates have a larger critical thickness
and slow strain relief than InGaAs grown on conventional
substrates.},
Key = {97053635881}
}
@article{96013016387,
Author = {Brown, A.S. and Bhattacharya, P. and Singh, J. and Zaman, P. and Sen, S. and Turco, F.},
Title = {Dependence of Al0.48In0.52As Schottky
diode properties on molecular beam epitaxial growth
temperature},
Journal = {Applied Physics Letters},
Volume = {68},
Number = {2},
Pages = {220 -},
Year = {1996},
url = {http://dx.doi.org/10.1063/1.116466},
Key = {96013016387}
}
@article{96083280775,
Author = {Carter-Coman, Carrie and Brown, April S. and Bicknell-Tassius, Robert and Jokerst, Nan Marie and Allen,
Mark},
Title = {Strain-modulated epitaxy: a flexible approach to 3-D band
structure engineering without surface patterning},
Journal = {Applied Physics Letters},
Volume = {69},
Number = {2},
Pages = {257 -},
Year = {1996},
url = {http://dx.doi.org/10.1063/1.117942},
Key = {96083280775}
}
@article{96073255513,
Author = {Carter-Coman, Carrie and Brown, April S. and Bicknell-Tassius, Robert and Jokerst, Nan Marie and Fournier, Francoise and Dawson, Douglas E.},
Title = {Strain-modulated epitaxy: modification of growth kinetics
via patterned, compliant substrates},
Journal = {Journal of Vacuum Science & Technology B: Microelectronics
Processing and Phenomena},
Volume = {14},
Number = {3},
Pages = {2170 -},
Year = {1996},
url = {http://dx.doi.org/10.1116/1.588892},
Key = {96073255513}
}
@article{97013489581,
Author = {Cat, Huy H. and Gentile, Antonio and Eble, John C. and Lee,
Myunghee and Vendier, Olivier and Joo, Young Joong and Wills, D. Scott and Brooke, Martin and Jokerst, Nan Marie and Brown, April S.},
Title = {SIMPil: An OE integrated SIMD architecture for focal plane
processing applications},
Journal = {International Conference on Massively Parallel Processing
Using Optical Interconnections (MPPOI), Proceedings},
Pages = {44 - 52},
Address = {Maui, HI, USA},
Year = {1996},
url = {http://dx.doi.org/10.1109/MPPOI.1996.559035},
Keywords = {Digital signal processing;Thin film devices;Integrated
optoelectronics;Image processing;Edge detection;Image
compression;Computer architecture;},
Abstract = {Focal plane processing applications present a growing
computing need for portable telecomputing and videoputing
systems. This paper demonstrates the integration of digital
processing, analog interface circuitry, and thin film OE
devices into a compact computing package. The SIMPil
architecture provides a programmable, silicon efficient SIMD
processor for effective execution of early image processing
applications such as edge detection, convolution, and
compression. Results from a demonstration SIMPil node are
presented including its microarchitecture, and performance
on image processing applications.},
Key = {97013489581}
}
@article{96083301631,
Author = {Carter-Coman, C. and Brown, A.S. and Jokerst, N.M. and Dawson, D.E. and Bicknell-Tassius, R. and Feng, Z.C. and Rajkumar, K.C. and Dagnall, G.},
Title = {Strain accommodation in mismatched layers by molecular beam
epitaxy: Introduction of a new compliant substrate
technology},
Journal = {Journal of Electronic Materials},
Volume = {25},
Number = {7},
Pages = {1044 - 1048},
Year = {1996},
Keywords = {Substrates;Strain;Growth (materials);Kinetic
theory;Epitaxial growth;Thin films;},
Abstract = {Compliant substrates allow a new approach to the growth of
strained epitaxial layers, in which part of the strain is
accommodated in the substrate. In this article compliant
substrates are discussed and a new compliant substrate
technology based on bonded thin flim substrates is
introduced. This technology has several advantages over
previously published methods, including the ability to
pattern both the top and bottom of the material. A new
concept enabled by this compliant substrate technology,
strain modulated epitaxy, will be introduced. Using this
technique, the properties of the semiconductor material can
be controlled laterally across a substrate. Results of two
experiments are presented in which low composition
In<sub>x</sub>Ga<sub>1-x</sub>As was grown by molecular beam
epitaxy on GaAs compliant substrates at thicknesses both
greater than and less than the conventional critical
thickness. It was found that for t gt; t<sub>c</sub>, there
was an inhibition of defect production in the epitaxial
films grown on the compliant substrates as compared to those
grown on conventional reference substrates. For t <
t<sub>c</sub>, photoluminescence and x-ray diffraction show
the compliant substrates to be of excellent quality and
uniformity as compared to conventional substrates.},
Key = {96083301631}
}
@article{5324747,
Author = {Gilbert, E.P. and Reynolds, P.A. and Brown, A.S. and White,
J.W.},
Title = {n-paraffin solid solutions: modification of phase separation
with carbon number},
Journal = {Chem. Phys. Lett. (Netherlands)},
Volume = {255},
Number = {4-6},
Pages = {373 - 7},
Year = {1996},
url = {http://dx.doi.org/10.1016/0009-2614(96)00371-5},
Keywords = {density;neutron diffraction;organic compounds;solid
solutions;},
Abstract = {Small-angle neutron scattering is used to monitor microphase
formation in the solid state in equimolar binary hydrocarbon
systems C<sub>n</sub>H<sub>2n+2</sub>:C<sub>m</sub>D<sub>2m+2</sub>
for selected n=20-34 and m=36. Microphase formation is
maximum for n=28 and negligible for n=20, 32 and 34. n=30 is
found to be intermediate. These observations are explicable
in terms of increasing molar volume differences between the
two components forming the mixture. As the chain length
difference increases, the formation of a lamellar microphase
occurs in preference to a continuous solid solution until
this is itself overtaken by two-phase separation},
Key = {5324747}
}
@article{95062757008,
Author = {Cat, Huy H. and Wills, D. Scott and Jokerst, Nan Marie and Brooke, Martin A. and Brown, April S.},
Title = {Three-dimensional, massively parallel, optically
interconnected silicon computational hardware and
architectures for high-speed IR scene generation},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {2469},
Pages = {141 - 145},
Address = {Orlando, FL, USA},
Year = {1995},
url = {http://dx.doi.org/10.1117/12.210584},
Keywords = {Optical interconnects;Performance;Thin films;Optoelectronic
devices;Semiconducting silicon;Integrated circuits;Parallel
processing systems;Semiconducting indium
compounds;Manufacture;Testing;Cost effectiveness;},
Abstract = {High frame rate infrared scene generation depends on high
performance digital processors that are tightly coupled to
infrared emitter arrays. Massively parallel image generation
hardware can realize the type of high throughput, high frame
rate processing that will characterize the next generation
of scene generators. This work outlines projects in
massively parallel, high throughput image generation
hardware using thin film optoelectronic devices which are
integrated directly onto low cost silicon integrated
circuits. For basic scene generation, an array of thin film
emitters are placed on top of digital single instruction
stream, multiple data stream (SIMD) parallel processors to
provide high performance focal plane generation in a
monolithic system. For more complex scene generation, low
cost stacked silicon integrated circuits, using
through-silicon wafer optoelectronic channels for three
dimensional interconnections, form an extremely dense, high
throughput, three dimensional parallel processing system.
Thin film InGaAsP devices, which operate at wavelengths to
which silicon is transparent, are integrated on top of
standard foundry silicon integrated circuits so that stacked
processor chips can communicate vertically. High speed
analog interface circuitry on the Si integrated circuits
provides a high bandwidth link between the devices and the
digital processing circuitry. This processing approach
provides tremendous generality for high frame rate image
generation applications in a compact system. Issues
addressed include system interfacing, power management,
manufacturing tolerances, testing and repair, and system
cost and effectiveness.},
Key = {95062757008}
}
@article{95052696922,
Author = {Rosenbaum, Steven E. and Kormanyos, Brian K. and Jelloian,
Linda M. and Matloubian, Mehran and Brown, April S. and Larson, Lawrence E. and Nguyen, Loi D. and Thompson, Mark A. and Katehi, Linda P.B. and Rebeiz, Gabriel
M.},
Title = {155- and 213-GHz AlInAs/GaInAs/InP HEMT MMIC
oscillators},
Journal = {IEEE Transactions on Microwave Theory and
Techniques},
Volume = {43},
Number = {4 pt 2},
Pages = {927 - 933},
Address = {Ann Arbor, MI, USA},
Year = {1995},
url = {http://dx.doi.org/10.1109/22.375256},
Keywords = {Monolithic microwave integrated circuits;Semiconducting
gallium arsenide;Semiconducting aluminum
compounds;Semiconducting indium phosphide;Electric
charge;Gates (transistor);Semiconductor device
manufacture;Micrometers;Electron beams;Slot
antennas;Molecular beam epitaxy;High electron mobility
transistors;},
Abstract = {We report on the design and measurement of monolithic 155-
and 213-GHz quasi-optical oscillators using
AlInAs/GaInAs/InP HEMT's. These results are believed to be
the highest frequency three-terminal oscillators reported to
date. The indium concentration in the channel was 80% for
high sheet charge and mobility. The HEMT gates were
fabricated with self-aligned sub-tenth-micrometer
electron-beam techniques to achieve gate lengths on the
order of 50 nm and drain-source spacing of 0.25 μm.
Planar antennas were integrated into the fabrication process
resulting in a compact and efficient quasi-optical
Monolithic Millimeter-wave Integrated Circuit (MMIC)
oscillator.},
Key = {95052696922}
}
@article{94071336131,
Author = {Brown, A.S. and Schmitz, A.E. and Nguyen, L.D. and Henige,
J.A. and Larson, L.E.},
Title = {Growth of high performance InxGa1-xAs
(.52 < x <.9) - (Al.48In.52As)
high electron mobility transistors by MBE},
Journal = {IEEE International Conferece on Indium Phosphide and Related
Materials},
Pages = {263 - 266},
Address = {Santa Barbara, CA, USA},
Year = {1994},
url = {http://dx.doi.org/10.1109/ICIPRM.1994.328217},
Keywords = {Semiconducting indium compounds;Semiconductor
growth;Electron transport properties;Semiconductor device
structures;Molecular beam epitaxy;Semiconductor doping;Phase
transitions;Crystal lattices;Gates (transistor);Relaxation
processes;Electron transitions;High temperature
operations;},
Abstract = {The paper reports the successful attempts at significantly
improving the electron mobility in thin channel, device
structures with high two-dimensional electron gas (2DEG)
concentrations. InGaAs-AlInAs modulation-doped structures
were grown by MBE in a Riber 2300 system on (100)-oriented
InP substrates. The highest room temperature mobility
achieved to date for low sheet charge and high sheet charge
samples were realized in a structure with a 10nm 80% In
channel utilizing a stress-compensation prelayer.},
Key = {94071336131}
}
@article{4620585,
Author = {Schramm, J.E. and Hu, E.L. and Merz, J.L. and Brown, J.J. and Melendes, M.A. and Thompson, M.A. and Brown,
A.S.},
Title = {Highly selective reactive ion etch process for InP-based
device fabrication using methane/hydrogen/argon},
Journal = {J. Vac. Sci. Technol. B, Microelectron. Process. Phenom.
(USA)},
Volume = {11},
Number = {6},
Pages = {2280 - 3},
Address = {San Diego, CA, USA},
Year = {1993},
url = {http://dx.doi.org/10.1116/1.586890},
Keywords = {aluminium compounds;gallium arsenide;high electron mobility
transistors;III-V semiconductors;indium compounds;sputter
etching;},
Abstract = {The etch rates of GaInAs and AlInAs were characterized using
a mixture of methane, hydrogen, and argon as a function of
self-bias voltage. Effectively infinite etch selectivity
between GaInAs and AlInAs was found for voltages below 200
V. This highly selective etch process was applied to the
gate recess of a high electron mobility transistor device,
and preliminary device measurements were
made},
Key = {4620585}
}
@article{4604389,
Author = {Brown, J.J. and Brown, A.S. and Rosenbaum, S.E. and Schmitz,
A.S. and Matloubian, M. and Larson, L.E. and Melendes, M.A. and Thompson, M.A.},
Title = {Study of the dependence of Ga0.47In0.53As/Alx
In1-xAs power HEMT breakdown voltage on Schottky
layer design and device layout},
Journal = {IEEE Trans. Electron Devices (USA)},
Volume = {40},
Number = {11},
Pages = {2111 - 12},
Address = {Santa Barbara, CA, USA},
Year = {1993},
url = {http://dx.doi.org/10.1109/16.239781},
Keywords = {aluminium compounds;electric breakdown of solids;gallium
arsenide;high electron mobility transistors;III-V
semiconductors;indium compounds;power transistors;Schottky
effect;solid-state microwave devices;},
Abstract = {Summary form only given. A systematic study of the
improvement of Ga<sub>0.47</sub>In<sub>0.53</sub>As/Al<sub>x</sub>
In<sub>1-x</sub>As HEMT (high electron mobility transistor)
breakdown voltage by varying the Schottky layer design and
device geometry is presented. The HEMT structure
investigated is a modulation-doped Ga<sub>0.47</sub>In<sub>0.53</sub>As/Al<sub>x</sub>
In<sub>1-x</sub>As on InP device with a sheet of charge
placed at the center of the 300 Å wide channel. The
device with a gate length of 0.5 μm, a source-drain
spacing of 5μm, and an Al<sub>0.7</sub>In<sub>0.3</sub>As
Schottky layer exhibited the best breakdown characteristics
of |BV<sub>gd</sub>|=6.8 V and BV<sub>ds</sub>=7.8 V. The
typical transistor had a maximum transconductance of 500
mS/mm, a full channel current of 700 mA/mm for a gate bias
of 0.4 V, and a current gain cutoff frequency of over 80
GHz. The power performance was measured on 500-μm-wide
devices at 4 GHz and V<sub>ds</sub>=4.5 V. Under Class AB
operating conditions, the output power density, power-added
efficiency, and power gain were 0.45 W/mm, 59%, and 14.25
dB, respectively},
Key = {4604389}
}
@article{93040774349,
Author = {Matloubian, Mehran and Brown, April S. and Nguyen, Loi D. and Melendes, Melissa A. and Larson, Lawrence E. and Delaney, Michael J. and Pence, John E. and Rhodes, Richard
A. and Thompson, Mark A. and Henige, Joseph
A.},
Title = {High-power V-band AlInAs/GaInAs on InP HEMT's},
Journal = {IEEE Electron Device Letters},
Volume = {14},
Number = {4},
Pages = {188 - 189},
Year = {1993},
url = {http://dx.doi.org/10.1109/55.215155},
Keywords = {Semiconducting indium phosphide;Semiconducting aluminum
compounds;Semiconducting gallium compounds;},
Abstract = {We report on the dc and RF performance of δ-doped
channel AlInAs/GaInAs on InP power HEMT's. A 450-μm-wide
device with a gate length of 0.22 μm has achieved an
output power of 150 mW (at the 1-dB gain compression point)
with power-added efficiency of 20% at 57 GHz. The device has
a saturated output power of 200 mW with power-added
efficiency of 17%. This is the highest output power measured
from a single InP-based HEMT at this frequency, and
demonstrates the feasibility of these HEMT's for high-power
applications in addition to low-noise applications at V
band.},
Key = {93040774349}
}
@article{94061318557,
Author = {Rosenbaum, Steven E. and Jelloian, Linda M. and Brown, April
S. and Thompson, Mark A. and Matloubian, Mehran and Larson,
Lawrence E. and Lohr, Ross and Kormanyos, Brian K. and Rebeiz, Gabriel M. and Katehi, Linda P.B.},
Title = {213 GHz AlInAs/GaInAs/InP HEMT MMIC oscillator},
Journal = {Technical Digest - International Electron Devices
Meeting},
Pages = {924 - 926},
Address = {Washington, DC, USA},
Year = {1993},
url = {http://dx.doi.org/10.1109/IEDM.1993.347470},
Keywords = {Equivalent circuits;Molecular beam epitaxy;Field effect
transistors;Heterojunctions;Substrates;},
Abstract = {We have fabricated submillimeter-wave MMIC oscillator
circuits using AlInAs/GaInAs/ HEMTs on InP substrates, which
have resulted in oscillators operating at fundamental
frequencies of 155 and 213 GHz. These results are believed
to be the highest frequency three-terminal oscillators
reported to date.},
Key = {94061318557}
}
@article{93101118299,
Author = {Rosenbaum, Steven E. and Jelloian, Linda M. and Larson,
Lawrence E. and Mishra, Umesh K. and Pierson, Deborah A. and Thompson, Mark S. and Liu, Takyiu and Brown, April
S.},
Title = {2-GHz three-stage AlInAs-GaInAs-InP HEMT MMIC low-noise
amplifier},
Journal = {IEEE Microwave and Guided Wave Letters},
Volume = {3},
Number = {8},
Pages = {265 - 267},
Year = {1993},
url = {http://dx.doi.org/10.1109/75.242220},
Keywords = {High electron mobility transistors;Monolithic integrated
circuits;Microwave devices;Spurious signal noise;Signal to
noise ratio;Semiconductor device manufacture;Semiconducting
indium phosphide;Semiconducting aluminum
compounds;Semiconducting gallium arsenide;Semiconductor
device structures;Electric losses;Performance;},
Abstract = {A three-stage monolithic microwave integrated circuit (MMIC)
low-noise amplifier (LNA) has been fabricated using
0.15-μm gate-length InP-based (AlInAs-GaInAs) high
electron mobility transistor (HEMT) technology. The LNA
exhibited less than 0.5-dB noise figure and greater than
35-dB gain from 2.25 to 2.5 GHz. The input and output return
loss exceeded 15 dB across the band. These results are
believed to be the best reported to date from a MMIC
amplifier in this frequency range.},
Key = {93101118299}
}
@article{93051596049,
Author = {Brown, A.S. and Henige, J.A. and Schmitz, A.E. and Larson,
L.E.},
Title = {Effect of growth conditions on the electrical and optical
properties of AlxIn1-xAs (0.48 < x
< 0.7)-Ga0.47In0.53As
heterostructures},
Journal = {Applied Physics Letters},
Volume = {62},
Number = {1},
Pages = {66 -},
Year = {1993},
url = {http://dx.doi.org/10.1063/1.108821},
Key = {93051596049}
}
@article{94041255772,
Author = {Matloubian, Mehran and Jelloian, Linda M. and Brown, April
S. and Nguyen, Loi D. and Larson, Lawrence E. and Delaney,
M.J. and Thompson, Mark A. and Rhodes, R.A. and Pence,
J.E.},
Title = {V-band high-efficiency high-power AlInAs/GaInAs/InP
HEMT's},
Journal = {IEEE Transactions on Microwave Theory and
Techniques},
Volume = {41},
Number = {12},
Pages = {2206 - 2210},
Year = {1993},
url = {http://dx.doi.org/10.1109/22.260707},
Keywords = {Semiconducting indium phosphide;Performance;Microwave
devices;Semiconductor device structures;Semiconductor
doping;Gates (transistor);Concentration (process);Semiconducting
aluminum compounds;Semiconducting gallium
compounds;Molecular beam epitaxy;Semiconductor device
manufacture;Ohmic contacts;},
Abstract = {In this paper, we report on the state-of-the-art power
performance of InP-based HEMT's at V-band. Power HEMT's were
fabricated using two different material layer structures.
The power performances of these HEMT's were measured at 59
GHz. We were able to achieve an output power of 155 mW with
4.9 dB gain, and power-added efficiency of 30 percent from a
448-μm-wide HEMT fabricated on a δ-doped channel
layer structure. By using a double-doped layer structure, we
were able to achieve an output power of 145 mW with 4.2 dB
gain, and power-added efficiency of 24 percent. Output power
of 288 mW with 3.6 dB gain and power-added efficiency of
20.4 percent were obtained by power combining two of the
δ-doped channel HEMT's. These combinations of output
power and efficiency are the best reported to date for
InP-based HEMT's, and are comparable to the best results
reported for AlGaAs/InGaAs on GaAs pseudomorphic HEMT's at
this frequency.},
Key = {94041255772}
}
@article{93071032443,
Author = {Matloubian, M. and Brown, A.S. and Nguyen, L.D. and Melendes, M.A. and Larson, L.E. and Delaney, M.J. and Thompson, M.A. and Rhodes, R.A. and Pence,
J.E.},
Title = {20-GHz high-efficiency AlInAs-GaInAs on InP power
HEMT},
Journal = {IEEE Microwave and Guided Wave Letters},
Volume = {3},
Number = {5},
Pages = {142 - 144},
Year = {1993},
url = {http://dx.doi.org/10.1109/75.217211},
Keywords = {Semiconducting aluminum compounds;Semiconducting indium
compounds;Semiconducting gallium arsenide;Power
amplifiers;Gain measurement;Electric power
measurement;},
Abstract = {A single stage 20-GHz power amplifier was developed using
double-doped AlInAs-GaInAs on InP HEMT. Output power of 516
mW (0.645 W/mm) with power-added efficiency of 47.1% with
7.1-dB gain were obtained from an 800-μm wide device. The
device had a saturated output power of more than 560 mW (0.7
W/mm). This is believed to be the highest combination of
output power, power density, gain, and power-added
efficiency reported for an InP-based FET at this
frequency.},
Key = {93071032443}
}
@article{94041266192,
Author = {Larson, L.E. and Matloubian, M.M. and Brown, J.J. and Brown,
A.S. and Rhodes, R. and Crampton, D. and Thompson,
M.},
Title = {AlInAs/GaInAs on InP HEMTs for low power supply voltage
operation of high power-added efficiency microwave
amplifiers},
Journal = {Electronics Letters},
Volume = {29},
Number = {15},
Pages = {1324 - 1326},
Year = {1993},
Keywords = {Microwave amplifiers;Semiconducting indium phosphide;Power
amplifiers;Semiconducting aluminum compounds;Semiconducting
gallium compounds;Performance;Millimeter waves;Electric
power supplies to apparatus;},
Abstract = {High power-added efficiency microwave power amplifier
results are reported for AlInAs/GaInAs on InP HEMTs operated
at relatively low power supply voltages (2.5-3 V). C-band
power amplifiers are reported with power-added efficiencies
as high as 67%, and output powers between 200 and 300 mW.
This excellent performance at low power supply voltages is
attributed to the high gain and low access resistances of
the devices, which leads to a high drain efficiency despite
the low power supply voltage.},
Key = {94041266192}
}
@article{94061322240,
Author = {Zakharov, N.D. and Liliental-Weber, Z. and Swider, W. and Brown, A.S. and Metzger, R.},
Title = {Structure of Ga0.47In0.53As epitaxial
layers grown on InP substrates at different
temperatures},
Journal = {Applied Physics Letters},
Volume = {63},
Number = {20},
Pages = {2809 -},
Year = {1993},
url = {http://dx.doi.org/10.1063/1.110294},
Key = {94061322240}
}
@article{93101087705,
Author = {Matloubian, M. and Jelloian, L.M. and Brown, A.S. and Nguyen, L.D. and Larson, L.E. and Delaney, M.J. and Thompson, M.A. and Rhodes, R.A. and Pence,
J.E.},
Title = {V-band high-efficiency high-power AlInAs/GaInAs/InP
HEMTs},
Journal = {IEEE MTT-S International Microwave Symposium
Digest},
Volume = {2},
Pages = {535 - 537},
Address = {Atlanta, GA, USA},
Year = {1993},
url = {http://dx.doi.org/10.1109/MWSYM.1993.276882},
Keywords = {Performance;Semiconducting indium phosphide;Semiconducting
gallium compounds;Semiconductor device structures;},
Abstract = {In this paper we report on the stage-of-the-art power
performance of InP-based HEMTs at 59 GHz. Using a 448 μm
wide HEMT with a gate-length of 0.15 μm, an output power
of 155 mW with 4.9 dB gain, and power-added efficiency of
30.1% were obtained. By power combining two of these HEMTs
we were able to achieve an output power of 288 mW with 3.6
dB gain and power-added efficiency of 20.4%. This is the
highest output power reported with such a high-efficiency
for InP-based HEMTs, and is comparable to the best results
reported for AlGaAs/InGaAs on GaAs pseudomorphic HEMTs at
this frequency.},
Key = {93101087705}
}
@article{94011191194,
Author = {Zakharov, N.D. and Liliental-Weber, Z. and Swider, W. and Washburn, J. and Brown, A.S. and Metzger,
R.},
Title = {Ordering in InGaAs/InAlAs layers},
Journal = {Journal of Electronic Materials},
Volume = {22},
Number = {12},
Pages = {1495 - 1498},
Year = {1993},
Keywords = {Semiconducting gallium arsenide;Semiconducting indium
compounds;Crystal structure;Crystal lattices;Transmission
electron microscopy;Order disorder transitions;},
Abstract = {The structure of InGaAs/InAlAs layers lattice matched to an
InP substrate, grown on either (100) or on (110) with a
4° tilt toward [111 over-bar ] at 500 and 300°C has
been investigated by transmission electron microscopy. High
perfection resulted for the layers grown on [001] oriented
substrates whereas growth on the near [110] substrates
resulted in compositional nonuniformities, macrosteps
formation, and ordering of the group III elements. This
difference in structural perfection between the two sets of
samples was also reflected in differences in electrical
properties.},
Key = {94011191194}
}
@article{4466016,
Author = {Nguyen, L.D. and Brown, A.S. and Thompson, M.A. and Jelloian, L.M.},
Title = {50 nm InP high electron mobility transistors},
Journal = {Microw. J. (USA)},
Volume = {36},
Number = {6},
Pages = {96, 98, 101 -},
Year = {1993},
Keywords = {high electron mobility transistors;III-V
semiconductors;indium compounds;semiconductor device
noise;solid-state microwave devices;},
Abstract = {A new type of field-effect transistor (FET), the indium
phosphide high electron mobility transistor (InP HEMT), has
recently emerged as an attractive candidate for low noise
applications at microwave and MM-wave frequencies. It
exhibits the lowest noise figures (<1 dB at 60 GHz), and
the highest cutoff frequencies (>300 GHz) among all
three-terminal semiconductor devices. Also, it is the only
type of transistor that has shown useful gain at frequencies
above 100 GHz (7.3 dB at 140 GHz). The authors describe the
scaling of InP HEMTs down to 50 nm gate length. By properly
designing the HEMT epitaxial layer and scaling its parasitic
resistances, significant improvements in device performance
are possible for FETs with gate lengths as short as 50 nm.
With further optimization, 50 nm InP HEMTs should extend the
operating frequency of three-terminal semiconductor devices
to at least 300 GHz, as well as provide a low cost
alternative to ultra low noise masers and SIS mixers at
microwave frequencies},
Key = {4466016}
}
@article{4469034,
Author = {Metzger, R.A. and Brown, A.S. and McCray, L.G. and Henige,
J.A.},
Title = {Structural and electrical properties of low temperature
GaInAs},
Journal = {J. Vac. Sci. Technol. B, Microelectron. Process. Phenom.
(USA)},
Volume = {11},
Number = {3},
Pages = {798 - 801},
Address = {Ottawa, Ont., Canada},
Year = {1993},
url = {http://dx.doi.org/10.1116/1.586792},
Keywords = {electronic conduction in crystalline semiconductor thin
films;gallium arsenide;III-V semiconductors;indium
compounds;molecular beam epitaxial growth;secondary ion mass
spectra;semiconductor epitaxial layers;semiconductor
growth;X-ray diffraction examination of materials;},
Abstract = {GaInAs lattice matched to InP was grown by molecular-beam
epitaxy over a temperature range of 100-450°C and
characterized by X-ray diffraction, resistivity, and
secondary ion mass spectroscopy, X-ray diffraction analysis
indicated the incorporation of excess As for samples grown
below 250°C. As-grown GaInAs was <i>n</i>-type with
electrical concentration increasing with decreasing growth
temperature, ranging from 5×10<sup>14</sup>
cm<sup>-3</sup> (450°C) to 1.8×10<sup>17</sup>
(150°C). Secondary ion mass spectroscopy indicated that
this behavior was not due to the incorporation of background
<i>n</i>-type dopants. Be- and Si-doped GaInAs at
5×10<sup>18</sup> cm<sup>-3</sup> showed full
electrical activation for growth temperatures down to
260°C, with only partial activation for Si and no
activation for Be for growth temperatures below
260°C},
Key = {4469034}
}
@article{4469039,
Author = {Brown, A.S. and Metzger, R.A. and Henige,
J.A.},
Title = {Growth and properties of AlInAs-GaInAs alloys and quantum
wells on (110)InP},
Journal = {J. Vac. Sci. Technol. B, Microelectron. Process. Phenom.
(USA)},
Volume = {11},
Number = {3},
Pages = {817 - 19},
Address = {Ottawa, Ont., Canada},
Year = {1993},
url = {http://dx.doi.org/10.1116/1.586753},
Keywords = {aluminium compounds;gallium arsenide;III-V
semiconductors;indium compounds;luminescence of inorganic
solids;molecular beam epitaxial growth;photoluminescence;semiconductor
growth;semiconductor quantum wells;spectral line
breadth;},
Abstract = {GaInAs and AlInAs structures have been grown on on-axis and
misoriented [4°-(111) In-plane] (110) InP substrates. In
general, the growth on the on-axis substrates shows a high
density of defects; while the surface morphology using
misoriented substrates is smooth. A smooth morphology is
obtained on on-axis (110) InP, however, with a low substrate
temperature and high V/III ratio. The photoluminescence
properties of the individual alloys grown on (110) show high
intensities, similar to that which can be obtained on (100)
substrates, but the peaks are significantly broadened and
shifted in energy. The interface quality of the
GaInAs-AlInAs (110) heterojunction, inferred from the
linewidths of quantum well emissions, is improved by growing
at higher temperature},
Key = {4469039}
}
@article{4306656,
Author = {Kiziloglu, K. and Hashemi, M.M. and Lie-Wei Yin and Yuan
Jing Li and Petroff, P.M. and Mishra, U.K. and Brown,
A.S.},
Title = {Rapid thermal annealing characteristics of bulk AlInAs/nP
and AlInAs/GaInAs/InP high electron mobility transistor
structures with planar silicon doping},
Journal = {J. Appl. Phys. (USA)},
Volume = {72},
Number = {8},
Pages = {3798 - 802},
Year = {1992},
url = {http://dx.doi.org/10.1063/1.352277},
Keywords = {aluminium compounds;annealing;carrier density;carrier
mobility;diffusion in solids;gallium arsenide;high electron
mobility transistors;III-V semiconductors;indium
compounds;rapid thermal processing;semiconductor
doping;silicon;two-dimensional electron gas;vacancies
(crystal);},
Abstract = {The effects of high temperature rapid thermal annealing
processes on carrier concentration and mobility of bulk
AlInAs and AlInAs/GaInAs high electron mobility transistor
structures with planar Si doping are studied. At annealing
temperatures of 700°C and 800°C, slight reduction in
mobilities and carrier concentration are observed in samples
annealed with a Si<sub>3</sub>N<sub>4</sub> cap or GaAs
pieces in close proximity. The reduction in mobility is
thought to be due to enhanced diffusion of the donor Si
atoms towards the two-dimensional electron gas channel.
Preferential vacancy enhanced diffusion of Si atoms towards
the surface is projected to be responsible for the loss in
carrier concentration. At these annealing temperatures, the
reduction in mobility in the samples annealed with
SiO<sub>2</sub> capping is more pronounced, and is as high
as 80% at the measurement temperature of 15 K. This behavior
is attributed to the outdiffusion of Ga and In atoms into
the oxide thereby creating vacancies and resulting in
interface mixing. Reduction in mobility and carrier
concentration are much more substantial in the 900°C
anneals done with Si<sub>3</sub>N<sub>4</sub> cap and GaAs
pieces in close proximity. This indicates the destruction of
the heterostructure integrity of the AlInAs/GaInAs
interface. For the particular anneal with a SiO<sub>2</sub>
cap at this temperature, the carrier concentration increases
above its reference value due to effective doping of the
ternary material by the back-diffusion Si atoms from the
SiO<sub>2</sub> cap},
Key = {4306656}
}
@article{93020691591,
Author = {Nguyen, Loi D. and Brown, April S. and Thompson, Mark A. and Jelloian, Linda M.},
Title = {50-nm self-aligned-gate pseudomorphic AlInAs/GaInAs high
electron mobility transistors},
Journal = {IEEE Transactions on Electron Devices},
Volume = {39},
Number = {9},
Pages = {2007 - 2014},
Year = {1992},
url = {http://dx.doi.org/10.1109/16.155871},
Keywords = {Semiconducting aluminum compounds;Semiconducting gallium
compounds;Integral equations;Gates (transistor);},
Abstract = {The design and fabrication of a class of 50-nm
self-aligned-gate pseudomorphic AlInAs/GaInAs high electron
mobility transistors (HEMTs) with potential for
ultra-high-frequency and ultra-low-noise applications are
reported. These devices exhibit an extrinsic
transconductance of 1740 mS/mm and an extrinsic current-gain
cutoff frequency of 340 GHz at room temperature. The
small-signal characteristics of a pseudomorphic and a
lattice-matched AlInAs/GaInAs HEMT with similar gate length
(50 nm) and gate-to-channel separation (17.5 nm) are
compared. The former demonstrates a 16% higher
transconductance and a 15% higher current-gain cutoff
frequency, but exhibits a 38% poorer output conductance. An
analysis of the high-field transport properties of
ultra-short gate-length AlInAs/GaInAs HEMTs shows that a
reduction of gate length from 150 to 50 nm neither enhances
nor reduces their average velocity. In contrast, the
addition of indium from 53% to 80% improves this parameter
by 19%.},
Key = {93020691591}
}
@article{95052701812,
Author = {Brown, A.S. and Nguyen, L.D. and Metzger, R.A. and Matloubian, M. and Schmitz, A.E. and Lui, M. and Wilson,
R.G. and Henige, J.A.},
Title = {Reduced silicon movement in GalnAs/AlInAs HEMT structures
with low temperature AlInAs spacers},
Pages = {281 - 286},
Address = {Seattle, WA, USA},
Year = {1992},
Key = {95052701812}
}
@article{92040460892,
Author = {Nguyen, Loi D. and Brown, April S. and Thompson, Mark A. and Jelloian, Linda M. and Larson, Larry E. and Matloubian,
Mehran},
Title = {650-angstrom self-aligned-gate pseudomorphic
Al0.48In0.52As/Ga0.20In0.80As
high electron mobility transistors},
Journal = {IEEE Electron Device Letters},
Volume = {13},
Number = {3},
Pages = {143 - 145},
Year = {1992},
url = {http://dx.doi.org/10.1109/55.144991},
Keywords = {Semiconducting Aluminum Compounds--Applications;Transistors,
High Electron Mobility--Fabrication;Semiconducting Indium
Compounds--Applications;Semiconducting Gallium
Compounds--Applications;},
Abstract = {The authors report on the design and fabrication of a
650-angstrom self-aligned-gate pseudomorphic
Al<sub>0.48</sub>In<sub>0.52</sub>As/Ga<sub>0.20</sub>In<sub>0.80</sub>As
high electron mobility transistor (HEMT) with a
state-of-the-art current gain cutoff frequency of over 300
GHz. This work clearly demonstrates the potential of
sub-0.1-μm gate-length HEMTs for near-future microwave
and millimeter-wave applications.},
Key = {92040460892}
}
@article{4547745,
Author = {Metzger, R.A. and Brown, A.S. and Wilson, R.G. and Liu, T. and Stanchina, W.E. and Nguyen, L.D. and Schmitz, A.E. and McCray, L.G. and Henige, J.A.},
Title = {The use of low temperature AlInAs and GaInAs lattice matched
to InP in the fabrication of HBTs and HEMTs},
Journal = {Low Temperature (LT) GaAs and Related Materials
Symposium},
Pages = {259 - 64},
Address = {Boston, MA, USA},
Year = {1992},
Keywords = {aluminium compounds;gallium arsenide;heterojunction bipolar
transistors;high electron mobility transistors;III-V
semiconductors;indium compounds;molecular beam epitaxial
growth;semiconductor growth;},
Abstract = {AlInAs and GaInAs lattice matched to InP and grown by MBE
over a temperature range of 200 to 350°C (normal growth
temperature of 500°C) has been used to enhance the
device performance of inverted (where the donor layer lies
below the channel) High Electron Mobility Transistors
(HEMTs) and Heterojunction Bipolar Transistors (HBTs),
respectively. The authors show that an AlInAs spacer grown
over a temperature range of 300 to 350°C and inserted
between the AlInAs donor layer and GaInAs channel
significantly reduces Si movement from the donor layer into
the channel. This produces an inverted HEMT with a channel
charge of 3.0×10<sup>12</sup> cm<sup>-2</sup> and
mobility of 9131 cm<sup>2</sup>/V-s, as compared to the same
HEMT with a spacer grown at 500°C resulting in a channel
charge of 2.3×10<sup>12</sup> cm<sup>-2</sup> and
mobility of 4655 cm<sup>2</sup>/V-s. They also show that a
GaInAs spacer grown over a temperature range of 300 to
350°C and inserted between the AlInAs emitter and GaInAs
base of an npn HBT significantly reduces Be movements from
the base into the emitter, thereby allowing higher Be base
dopings (up to 1×10<sup>20</sup> cm<sup>-3</sup>)
confined to 500 Å base widths, resulting in an
AlInAs/GaInAs HBT with an f<sub>max</sub> of 73 GHz and
f<sub>t</sub> of 110 GHz},
Key = {4547745}
}
@article{4179619,
Author = {Brown, A.S. and Nguyen, L.D. and Metzger, R.A. and Schmitz,
A.E. and Henige, J.A.},
Title = {Growth and properties of high mobility strained inverted
AlInAs-GaInAs modulation doped structures},
Journal = {J. Vac. Sci. Technol. B, Microelectron. Process. Phenom.
(USA)},
Volume = {10},
Number = {2},
Pages = {1017 - 19},
Address = {Austin, TX, USA},
Year = {1992},
url = {http://dx.doi.org/10.1116/1.586402},
Keywords = {aluminium compounds;electron gas;electron mobility;gallium
arsenide;high electron mobility transistors;III-V
semiconductors;impurity scattering;indium compounds;surface
segregation;},
Abstract = {GaInAs-AlInAs inverted modulation-doped structures exhibit
degraded two-dimensional electron gas (2DEG) transport
properties when grown under standard conditions. This
results from the surface segregation of Si from the donor
layer into the GaInAs channel layer. Consequently, the 2DEG
has poor mobility due to increased ionized impurity
scattering. The authors have obtained high mobility inverted
structures through the inhibition of this surface
segregation by growing the spacer layer at a greatly reduced
substrate temperature. Inverted modulation doped structures
optimized for high frequency device applications require the
use of thin channel layers. In order to obtain a large
charge density (>2.3×10<sup>12</sup>
cm<sup>-2</sup>) with high quality transport
characteristics, In-rich, strained channels are required.
This paper presents the results of an investigation of the
electronic and optical properties of strained, inverted,
thin-channel modulation doped structures. Channel
thicknesses of 50-200 Å and In compositions of 53% to
80% were investigated. A 300 K electron mobility of 13000
cm<sup>2</sup>/V s was obtained with a sheet charge density
of 2.4×10<sup>12</sup> cm<sup>-2</sup> for a 75
Å thick Ga<sub>0.27</sub>In<sub>0.73</sub>As
channel},
Key = {4179619}
}
@article{4107436,
Author = {Brown, A.S. and Metzger, R.A. and Henige, J.A. and Nguyen,
L. and Lui, M. and Wilson, R.G.},
Title = {Effect of Si movement on the electrical properties of
inverted AlInAs-GaInAs modulation doped structures},
Journal = {Appl. Phys. Lett. (USA)},
Volume = {59},
Number = {27},
Pages = {3610 - 12},
Year = {1991},
url = {http://dx.doi.org/10.1063/1.106394},
Keywords = {aluminium compounds;carrier mobility;electron gas;gallium
arsenide;Hall effect;III-V semiconductors;indium
compounds;semiconductor junctions;silicon;surface
segregation;},
Abstract = {Inverted modulation doped structures typically exhibit
degraded electrical characteristics. For the AlInAs-GaInAs
heterojunction system, the reduction in electron mobility
for two-dimensional electron gases formed at inverted
interfaces can be greater than 50% at 300 K as compared to
those formed at normal interfaces. The authors' data show
that the reduction in mobility is due to the movement of Si
into the GaInAs channel. The Si movement is found to be
dramatically reduced by growing the AlInAs spacer at the
inverted interface at a substrate temperature of
300-350°C. Device structures have been grown using this
technique which exhibit the highest conductivity obtained
for any 2DEG system},
Key = {4107436}
}
@article{91080271574,
Author = {Metzger, R.A. and Brown, A.S. and Stanchina, W.E. and Lui,
M. and Wilson, R.G. and Kargodorian, T.V. and McCray, L.G. and Henige, J.A.},
Title = {Growth and characterization of low temperature
AlInAs},
Journal = {Journal of Crytal Growth},
Volume = {111},
Number = {1-4},
Pages = {445 - 449},
Address = {La Jolla, CA, USA},
Year = {1991},
url = {http://dx.doi.org/10.1016/0022-0248(91)91017-5},
Keywords = {Molecular Beam Epitaxy;Photoluminescence;X-rays -
Diffraction;Mass Spectrometry;Semiconducting Indium
Phosphide;},
Abstract = {Al<sub>0.48</sub>In<sub>0.52</sub>As lattice matched to InP
and grown by MBE over a temperature range of 250 to
100°C and under an As<sub>4</sub> pressure of 1 ×
10<sup>-6</sup> to 2 × 10<sup>-5</sup> Torr has been
investigated. Over this temperature range of 250 to
100°C, resistivity decreases from 2 ×
10<sup>7</sup> to 3 × 10<sup>6</sup> Ω cm while
photoluminescence intensity decreases by two orders of
magnitude. Resistivity showed little sensitivity to change
in As<sub>4</sub> overpressure over the range investigated.
Single crystal samples grown in the range of 100 to
150°C showed nonstochiometric excess As of up to 1.4% as
determined by secondary ion mass spectrometry, and lattice
expansion of 0.1% as determined by X-ray diffraction.
Samples grown at temperatures greater than 200°C showed
no excess As or lattice expansion.},
Key = {91080271574}
}
@article{92020412149,
Author = {Schmitz, A. E. and Nguyen, L. D. and Brown, A. S. and Metzger, R. A.},
Title = {InP-based inverted high electron mobility
transistors},
Journal = {IEEE Transactions on Electron Devices},
Volume = {38},
Number = {12},
Pages = {2702 -},
Address = {Boulder, CO, USA},
Year = {1991},
url = {http://dx.doi.org/10.1109/16.158723},
Keywords = {Semiconducting Indium Phosphide;Semiconducting Aluminum
Compounds;},
Abstract = {Summary form only given. The fabrication and
characterization of an inverted high-electron-mobility
transistor (HEMT) in the AlInAs/GaInAs-on-InP material
system are reported. Inverted HEMTs, which have the donor
layer beneath the channel, have the potential for higher
transconductance, current gain cutoff frequency, and power
gain cutoff frequency than conventional HEMTs because the
gate can be placed closer to the two-dimensional electron
gas (2DEG).},
Key = {92020412149}
}
@article{92010390276,
Author = {Matloubian, M. and Nguyen, L. D. and Brown, A. S. and Larson, L. E. and Melendes, M. A. and Thompson, M.
A.},
Title = {High power and high efficiency AlInAs/GaInAs on InP
HEMTs},
Journal = {IEEE MTT-S International Microwave Symposium
Digest},
Volume = {2},
Pages = {721 - 724},
Address = {Boston, MA, USA},
Year = {1991},
url = {http://dx.doi.org/10.1109/MWSYM.1991.147105},
Keywords = {Microwave Measurements;Amplifiers, Power
Type;},
Abstract = {The authors report on the development of
AlInAs/GaInAs-on-InP power HEMTs (high electron mobility
transistors). Output power densities of more than 730 mW/mm
and 960 mW/mm with power-added efficiencies (PAE) of 50% and
40%, respectively, were achieved at 12 GHz. When biased for
maximum efficiency, a PAE of 59% and an output power of 470
mW/mm with 11.3 dB gain were obtained. These results
demonstrate the viability of these HEMTs for power
amplification. Considering that these HEMTs have an
f<sub>max</sub> of over 200 GHz, they should also have good
power performance at millimeter-wave frequencies.},
Key = {92010390276}
}
@article{92060514906,
Author = {Brown, A.S. and Nguyen, L.D. and Metzger, R.A. and Matloubian, M. and Schrnitz, A.E. and Lui, M. and Wilson,
R.G. and Henige, J.A.},
Title = {Reduced silicon movement in GaInAs/AlInAs HEMT structures
with low temperature AlInAs spacers},
Journal = {Institute of Physics Conference Series},
Volume = {120},
Pages = {281 - 286},
Address = {Seattle, WA, USA},
Year = {1991},
Keywords = {Silicon and Alloys - Diffusion;Semiconducting Gallium
Arsenide;Semiconducting Indium Compounds;Semiconducting
Aluminum Compounds;Molecular Beam Epitaxy -
Applications;},
Abstract = {High electron mobility transistors fabricated from
GaInAs/AlInAs modulation-doped structure currently exhibit
the highest current gain cut-off frequency, highest maximum
frequency of oscillation and lowest noise figure of any
three terminal device. The data presented show that the
degraded characteristics of the inverted modulation-doped
interface, as compared with the normal AlInAs on GaInAs,
result from the segregation of silicon in AlInAs. The
authors have reduced the magnitude of these deleterious
effects by growing a thin layer of AlInAs immediately
following the doped region at significantly reduced
substrate temperatures. The degree of silicon segregation as
a fucntion of substrate temperature is discussed.also},
Key = {92060514906}
}
@article{3947624,
Author = {Brown, A.S.},
Title = {An overview of microwave waveguide technology},
Journal = {Electrotechnology (UK)},
Volume = {2},
Number = {3},
Pages = {120 - 2},
Year = {1991},
Keywords = {guided electromagnetic wave propagation;waveguides;},
Abstract = {With the increasing demand for microwave circuitry in both
the consumer and industrial markets the engineering
expertise to develop these techniques is becoming a key
issue. The profusion of engineers now being faced with the
problems of signal processing in the gigahertz frequency
range is making a basic understanding of the principles an
essential skill for all electronics engineers. Point to
point digital radio, satellite TV, information systems,
physiotherapy treatment and radar are just a few examples of
this ever increasing application field. The author provides
an insight into transmission principles in the SHF band and
beyond. A lower limit of 3 GHz is assumed. The author
considers waveguide propagation in the TE, TEM and TM modes.
Construction practicalities, circular waveguides, health
aspects and applications are discussed},
Key = {3947624}
}
@article{3846550,
Author = {Brown, A.S. and Spackman, M.A.},
Title = {A model study of the κ-refinement procedure for
fitting valence electron densities},
Journal = {Acta Crystallogr. A, Found. Crystallogr.
(Denmark)},
Volume = {A47},
Pages = {21 - 9},
Year = {1991},
url = {http://dx.doi.org/10.1107/S0108767390009163},
Keywords = {HF calculations;X-ray crystallography calculation
methods;},
Abstract = {Monopole electron-density deformations for first- and
second-row atoms are obtained using Hirshfeld partitioning
of near Hartree-Fock limit electron densities for 28
diatomics. The κ-refinement model [Coppens, Guru Row,
Leung, Stevens, Becker and Yang, Acta Cryst. A35, 63-72
(1979)] is applied to these monopole deformations and its
success in modelling them is gauged by means of deformation
radial distribution plots, <i>r</i><sup>2</sup>Δρ(<i>r</i>),
and κ and charge-transfer values. The
κ-refinement procedure proves to be remarkably
successful in modelling the monopole deformations in this
work. This in large part explains the successful application
of the κ-refinement model to X-ray diffraction data,
where it is capable of yielding an excellent point-charge
model of the electrostatic potential in molecules and
crystals},
Key = {3846550}
}
@article{3757163,
Author = {Brown, A.S.},
Title = {The effects and implications of ESD on semiconductor
technology},
Journal = {Electrotechnology (UK)},
Volume = {1},
Number = {4},
Pages = {217 - 19},
Year = {1990},
Keywords = {electrostatic discharge;integrated circuit
manufacture;integrated circuit technology;VLSI;},
Abstract = {Since the development and implementation of large scale and
very large scale integration techniques (LSI and VLSI),
manufacturers have become increasingly aware of the damaging
and destructive properties of electrostatic discharge (ESD)
on semiconductor materials. The author expresses the opinion
that this phenomena has not been taken seriously until
relatively recently, and although semiconductor
manufacturers have observed the necessary precautions for
many years the practice is only now diversifying into
installation, assembly, servicing and repair operations. The
generation of ESD and its damaging effects are described,
and practical methods of protection are presented, including
a check list of precautions that should be
taken},
Key = {3757163}
}
@article{3802514,
Author = {Mishra, U.K. and Brown, A.S. and Jelloian, L.M. and Thompson, M. and Rosenbaum, S.E. and Nguyen, L.D. and Solomon, P.M. and Kiehl, R. and Kwark, Y.H.},
Title = {Room temperature and cryogenic performance of self-aligned
AlInAs-GaInAs HEMTs with 0.15 μm gate
length},
Journal = {Proc. SPIE - Int. Soc. Opt. Eng. (USA)},
Volume = {1288},
Pages = {21 - 9},
Address = {San Diego, CA, USA},
Year = {1990},
Keywords = {aluminium compounds;gallium arsenide;high electron mobility
transistors;III-V semiconductors;indium compounds;plasma
deposition;solid-state microwave devices;},
Abstract = {A novel self-aligned technique for 0.15 μm gate length
AlInAs-GaInAs HEMTs has been demonstrated. Devices with an
oxide sidewall yielded an f<sub>T</sub> of 177 GHz whereas
devices with no sidewall exhibited an f<sub>T</sub> greater
than 250 GHz. The difference has been related to process
damage during plasma deposition of SiO<sub>2</sub>. An
extrinsic f<sub>T</sub> of 292 GHz was measured at 77
K},
Key = {3802514}
}
@article{94071327430,
Author = {Delaney, M.J. and Brown, A.S. and Mishra, U.K. and Chou,
C.S. and Larson, L.E. and Nguyen, L. and Jensen,
J.},
Title = {Low temperature MBE growth of GaAs and AllnAs for high speed
devices},
Pages = {189 - 194},
Address = {Karuizawa, Jpn},
Year = {1990},
Key = {94071327430}
}
@article{3695770,
Author = {Mishra, U.K. and Brown, A.S. and Jensen,
J.F.},
Title = {High performance AlInAs-GaInAs HEMTs and
HBTs},
Journal = {Gallium Arsenide and Related Compounds 1989. Proceedings of
the Sixteenth International Symposium},
Pages = {605 - 12},
Address = {Karuizawa, Japan},
Year = {1990},
Keywords = {aluminium compounds;gallium arsenide;heterojunction bipolar
transistors;high electron mobility transistors;III-V
semiconductors;indium compounds;semiconductor
junctions;},
Abstract = {AlInAs-GaInAs HEMTs with f<sub>t</sub>>2000 GHz and
minimum noise figure of 0.8 dB at 63.5 GHz have been
fabricated. Ring oscillators with gate delay of 6 pS and
static dividers with operating frequency of 26.7 GHz have
been demonstrated. AlInAs-GaInAs HBTs with f<sub>T</sub> of
49 GHz, f<sub>max</sub> of 62 GHz have been achieved. The
maximum operating frequency of static dividers was 15
GHz},
Key = {3695770}
}
@article{89095061495,
Author = {Brown, A.S. and Mishra, U.K. and Rosenbaum,
S.E.},
Title = {Effect of interface and alloy quality on the DC and RF
performance of Ga0.47In0.53As-Al0.48In0.52As
HEMT's.},
Journal = {IEEE Transactions on Electron Devices},
Volume = {36},
Number = {4 pt 1},
Pages = {641 - 645},
Year = {1989},
url = {http://dx.doi.org/10.1109/16.22468},
Keywords = {Electric Conductivity;Semiconducting Gallium
Compounds;Semiconducting Aluminum Compounds;},
Abstract = {Ga<sub>0.47</sub>In<sub>0.53</sub>As-Al<sub>0.48</sub>In<sub>0.52</sub>As
high-electron-mobility transistors (HEMTs) were fabricated
in materials with varying degrees of alloy and interface
disorder. The conductivities of the expitaxial layers are
highest for material with the smallest amount of interface
roughness and lowest for samples with poor-quality
interfaces. The transconductances and unity current gain
cutoff frequencies of the fabricated devices with 0.2-μm
gates are similarly affected.},
Key = {89095061495}
}
@article{90056030370,
Author = {Delaney, M.J. and Brown, A.S. and Mishra, U.K. and Chou,
C.S. and Larson, L.E. and Nguyen, L. and Jensen,
J.},
Title = {Low temperature MBE growth of GaAs and AlInAs for high speed
devices},
Pages = {64 - 72},
Address = {Ithaca, NY, USA},
Year = {1989},
url = {http://dx.doi.org/10.1109/CORNEL.1989.79822},
Keywords = {Transistors, Field Effect--Fabrication;Molecular Beam
Epitaxy;Semiconducting Gallium Arsenide--Growth;},
Abstract = {Low-temperature GaAs buffer technology was used to fabricate
high-performance 0.2-μm-gate-length, spike-doped GaAs
MESFETs. A 400.0-nm low-temperature GaAs buffer was grown by
molecular beam epitaxy (MBE) at a substrate temperature of
300°C. The substrate temperature was raised to 580°C
for a brief in situ anneal and followed by the growth of the
active spike-doped GaAs MESFET structure. The peak extrinsic
transconductance, g<sub>m</sub>, was 600 mS/mm with an
average pinch-off voltage, V<sub>po</sub>, of -0.6 V. An
output conductance, g<sub>o</sub>, of 24 mS/mm resulted in a
voltage gain of 25. The extrapolated f<sub>T</sub> of the
devices was 79 GHz. Static SCFL (source-coupled FET logic)
frequency dividers fabricated in this technology exhibit a
maximum clock rate of 22 GHz. Low-temperature AlInAs buffer
growth has been applied to GaInAs/AlInAs HEMT
(high-electron-mobility transistor devices on InP. A
250.0-nm AlInAs buffer was grown at a substrate temperature
of 150°C, followed by an anneal under arsenic
overpressure and a GaInAs/AlInAs superlattice prior to the
HEMT structure, which is grown at T</sub> = 510°C.
Devices fabricated with 0.2-μm gates had g<sub>m</sub> of
670 mS/mm and g<sub>o</sub> of 2.55 mS/mm, giving a voltage
gain of 250.},
Key = {90056030370}
}
@article{3506085,
Author = {Brown, A.S. and Mishra, U.K. and Larson, L.E. and Rosenbaum,
S.E.},
Title = {The elimination of DC I-V anomalies in Ga0.47In0.53As-Al0.48In0.52As
HEMTs},
Journal = {Gallium Arsenide and Related Compounds 1988. Proceedings of
the Fifteenth International Symposium},
Pages = {445 - 8},
Address = {Atlanta, GA, USA},
Year = {1989},
Keywords = {aluminium compounds;gallium arsenide;high electron mobility
transistors;III-V semiconductors;indium compounds;p-n
heterojunctions;},
Abstract = {GaInAs-AlInAs HEMTs have improved DC and RF performance as
compared with GaInAs-(AlGa)As HEMTs. The drain-source I-V
characteristics exhibit a kink related to trap ionization in
the AlInAs buffer. This kink is eliminated by using a GaInAs
buffer. Sidegating is also dramatically reduced with the
GaInAs buffer},
Key = {3506085}
}
@article{90120074434,
Author = {Mishra, U.K. and Brown, A.S. and Jelloian, L.M. and Thompson, M. and Nguyen, L.D. and Rosenbaum,
S.E.},
Title = {Novel high performance self-aligned 0.15 micron long T-gate
AlInAs-GaInAs HEMTs},
Journal = {Technical Digest - International Electron Devices
Meeting},
Pages = {101 - 104},
Address = {Washington, DC, USA},
Year = {1989},
url = {http://dx.doi.org/10.1109/IEDM.1989.74237},
Keywords = {Semiconducting Aluminum Compounds;Semiconducting Gallium
Compounds;},
Abstract = {A novel self-aligned technique for 0.15-μm-gate-length
HEMTs (high electron mobility transistors) has been
demonstrated. This technology uses a 0.15-μm-long T-gate
structure defined by e-beam lithography with a
SiO<sub>2</sub> sidewall to implement the self-aligned
scheme. The resultant device has low source and drain
resistances, low gate resistance (200 Ω/mm), and a
passivating layer over the active channel. Devices with an
oxide sidewall yielded an f<sub>T</sub> of 177 GHz, whereas
devices with no sidewall exhibited an f<sub>T</sub> greater
than 250 GHz. The difference has been related to process
damage during plasma deposition of SiO<sub>2</sub>.},
Key = {90120074434}
}
@article{90076090867,
Author = {Brown, April S. and Chou, Chia S. and Delaney, Michael J. and Hooper, Catherine E. and Jensen, Joseph F. and Larson,
Lawrence E. and Mishra, Umesh K. and Nguyen, Loi D. and Thompson, Mark S.},
Title = {Low-temperature buffer AlInAs/GaInAs on InP HEMT technology
for ultra-high-speed integrated circuits},
Journal = {Technical Digest - GaAs IC Symposium (Gallium Arsenide
Integrated Circuit)},
Pages = {143 - 146},
Address = {San Diego, CA, USA},
Year = {1989},
Keywords = {Logic Devices--Gates;Electronic Circuits, Flip
Flop;Crystals--Epitaxial Growth;},
Abstract = {A report is presented on the development of a planar
low-temperature buffer AlInAs/GaInAs on InP
high-electron-mobility transistor (HEMT) technology for use
in digital and analog integrated circuits. This technology
is attractive for circuit applications because of the high
achievable f<sub>T</sub> and f<sub>max</sub>, low output
conductance and gate leakage current, and reduced
susceptibility to backgating effects. Two alternative logic
families--UFL and SCFL (source-coupled FET logic)--were
chosen for the realization of digital circuits. Measurements
on the UFL ring oscillators exhibited a minimum gate delay
of 13 pS with a power dissipation of 1.1 mW/gate at room
temperature. The gate delay rose to 25 pS when the power
dissipation increased to 3 mW/gate. This gate delay is
expected to drop significantly with reductions in diode
level-shift series resistance and improvements in transistor
f<sub>T</sub>. The most complex SCFL circuit tested was a
divide-by-eight counter. The SCFL circuits were configured
as flip-flops in the divide-by-eight mode. The circuit
operated at a maximum clock rate of 12.5
GHz.},
Key = {90076090867}
}
@article{90025161317,
Author = {Mishra, Umesh K. and Brown, April S. and Delaney, M.J. and Greiling, Paul T. and Krumm, Charles F.},
Title = {AlInAs-GaInAs HEMT for microwave and millimeter-wave
applications},
Journal = {IEEE Transactions on Microwave Theory and
Techniques},
Volume = {37},
Number = {9},
Pages = {1279 - 1285},
Year = {1989},
url = {http://dx.doi.org/10.1109/22.32210},
Keywords = {Semiconducting Indium Compounds--Applications;Microwave
Devices;Semiconducting Aluminum Compounds--Applications;Amplifiers;},
Abstract = {The status of lattice-matched high-electron-mobility
transistors (HEMTs) and pseudomorphic AlInAs-GaInAs grown on
In substrates is reviewed. The best lattice-matched devices
with 0.1-μm gate length had a transconductance
g<sub>m</sub> = 1080 mS/mm and a unity current gain cutoff
frequency f<sub>T</sub> = 178 GHz, whereas similar
pseudomorphic HEMTs had g<sub>m</sub> = 1160 mS/mm and
f<sub>T</sub> = 210 GHz. Single-stage V-band amplifiers
demonstrated 1.3- and 1.5-dB noise figures and 9.5- and
8.0-dB associated gains for the lattice-matched and
pseudomorphic HEMTs, respectively. The best performance
achieved was a minimum noise figure of F<sub>min</sub> = 0.8
dB with a small-signal gain of G<sub>a</sub> = 8.7
dB.},
Key = {90025161317}
}
@article{90056020715,
Author = {Mishra, U.K. and Brown, A.S. and Jelloian, L.M. and Melendes, M.A. and Thompson, M. and Rosenbaum, S.E. and Larson, L.E.},
Title = {Impact of buffer layer design on the performance of
AlInAs-GaInAs HEMT's},
Journal = {IEEE Transactions on Electron Devices},
Volume = {36},
Number = {11 pt 1},
Pages = {2616 -},
Address = {Cambridge, MA, USA},
Year = {1989},
url = {http://dx.doi.org/10.1109/16.43731},
Keywords = {Electrons--Transport Properties;Semiconductor
Materials--Doping;},
Abstract = {Summary form only given. The authors report a study of the
impact of buffer layer design on the characteristics of
Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.47</sub>In<sub>0.53</sub>As
HEMTs (high-electron-mobility transistors). The aim of the
study is to understand and correct the problem of high
output conductance observed in devices with a high
transconductance. Devices with 1.0-μm gate lengths were
fabricated using modulation-doped Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.47</sub>In<sub>0.53</sub>As
epitaxial layes which had sheet charge densities between 3
× 10<sup>12</sup> and 3.5 × 10<sup>12</sup>
cm<sup>-2</sup> and mobilities at 300 K between 9000 and
10,000 cm</sup> V<sup>-1</sup> S<sup>-1</sup>. The different
buffer layer designs used were: 1) a standard undoped
Al<sub>0.48</sub>In<sub>0.52</sub>As buffer 250-nm-thick; 2)
an Al<sub>0.48</sub>In<sub>0.52</sub>As buffer with a
20-angstrom thick highly doped p-type region 50 angstrom
below the channel; 3) A Ga<sub>0.47</sub>In<sub>0.53</sub>As
buffer with a 20-angstrom-thick highly doped p-type region
below the channel; and 4) a low-temperature AlInAs buffer
layer. The device with the low-temperature AlInAs had the
best output characteristics, signifying that it was the best
mode of confining electrons in the channel.},
Key = {90056020715}
}
@article{90046020788,
Author = {Brown, April S. and Mishra, Umesh K. and Chou, C.S. and Hooper, C.E. and Melendes, M.A. and Thompson, M. and Larson,
L.E. and Rosenbaum, S.E. and Delaney, M.J.},
Title = {AlInAs-GaInAs HEMT's utilizing low-temperature AlInAs
buffers grown by MBE},
Journal = {IEEE Electron Device Letters},
Volume = {10},
Number = {12},
Pages = {565 - 567},
Year = {1989},
url = {http://dx.doi.org/10.1109/55.43141},
Keywords = {Semiconducting Aluminum Compounds;Crystals--Epitaxial
Growth;Millimeter Waves;},
Abstract = {Low-temperature AlInAs buffer layers incorporated in
AlInAs-GaInAs HEMT epitaxial layers grown by MBE are
discussed. A growth temperature of 150°C followed by a
short anneal is shown to eliminate kinks in the device I-V
characteristic and sidegating and to reduce the output
conductance dramatically.},
Key = {90046020788}
}
@article{89070310715,
Author = {Jensen, Joseph F. and Mishra, Umesh K. and Brown, April S. and Salmon, Linton G. and Delaney, M.J.},
Title = {Ultrahigh speed static and dynamic frequency divider
circuits},
Journal = {Microwave Journal},
Volume = {32},
Number = {3},
Pages = {10 -},
Year = {1989},
Keywords = {Electronic Equipment Manufacture;Electronic Equipment
Testing;Transistors, Field Effect;Semiconducting Gallium
Arsenide;Semiconducting Aluminum Compounds;},
Abstract = {This paper describes the design, fabrication and testing of
high speed GaAs MESFET and AlInAs/GaInAs HEMT frequency
divider circuits. GaAs MESFET static frequency dividers
operate at frequencies up to 18 GHz, and GaAs MESFET dynamic
dividers operate at frequencies up to 26.6 GHz. When the
same static divide designs were implemented in AlInAs/GaInAs
HEMT technology, the performance improved to frequencies up
to 25.4 GHz. Electrooptic testing techniques were used to
verify the performance of the GaAs MESFET
dividers.},
Key = {89070310715}
}
@article{89125160265,
Author = {Delaney, M.J. and Chou, C.S. and Larson, L.E. and Jensen,
J.F. and Deakin, D.S. and Brown, A.S. and Hooper, W.W. and Thompson, M.A. and McCray, L.G. and Rosenbaum,
S.E.},
Title = {GaAs MESFET digital integrated circuits fabricated with low
temperature buffer technology},
Journal = {Proceedings of the Custom Integrated Circuits
Conference},
Pages = {18 - 3},
Address = {San Diego, CA, USA},
Year = {1989},
url = {http://dx.doi.org/10.1109/CICC.1989.56782},
Keywords = {Semiconducting Gallium Arsenide;Transistors, Field
Effect;Electronic Circuits, Frequency Dividing;},
Abstract = {High-performance digital integrated circuits have been
fabricated with low-temperature buffer GaAs MESFET
technology. The materials structure eliminates side-gating
and light sensitivity, and improves FET performance.
Individual transistors with a 0.2-μm gate length have a
g<sub>m</sub> of 600 mS/mm and an extrapolated f<sub>T</sub>
of 80 GHz. Static SCFL frequency dividers fabricated in this
technology exhibit a maximum clock rate of 22
GHz.},
Key = {89125160265}
}
@article{90015161235,
Author = {Delaney, M.J. and Chou, C.S. and Larson, Lawrence E. and Jensen, Joseph F. and Deakin, D.S. and Brown, April S. and Hooper, William W. and Thompson, M.A. and McCray, L.G. and Rosenbaum, Steven E.},
Title = {Low-temperature buffer GaAs MESFET technology for high-speed
integrated circuit applications},
Journal = {IEEE Electron Device Letters},
Volume = {10},
Number = {8},
Pages = {355 - 357},
Year = {1989},
url = {http://dx.doi.org/10.1109/55.31755},
Keywords = {Transistors, Field Effect;Semiconducting Gallium
Arsenide;Logic Devices;},
Abstract = {The fabrication of high-performance digital integrated
circuits with low-temperature buffer (LTB) GaAs MESFET
technology is presented. Individual 0.2-μm-gate-length
transistors show a g<sub>m</sub> of 600 mS/mm and an
extrapolated f<sub>T</sub> of 80 GHz. Backgating and light
sensitivity are eliminated with the LTB technology. Static
source-coupled FET logic frequency dividers exhibit a
maximum clock rate of 22 GHz.},
Key = {90015161235}
}
@article{90035240892,
Author = {Mishra, Umesh K. and Jensen, Joseph F. and Rensch, D.B. and Brown, April S. and Stanchina, William E. and Trew, Robert
J. and Pierce, M.W. and Kargodorian, Tsolag
V.},
Title = {Self-aligned AlInAs-GaInAs heterojunction bipolar
transistors and circuits},
Journal = {IEEE Electron Device Letters},
Volume = {10},
Number = {10},
Pages = {467 - 469},
Year = {1989},
url = {http://dx.doi.org/10.1109/55.43102},
Keywords = {Semiconducting Aluminum Compounds;Semiconducting Gallium
Compounds;Integrated Circuits;Electronic Circuits, Flip
Flop;Electronic Circuits, Frequency Dividing;},
Abstract = {AlInAs-GaInAs heterojunction bipolar transistors (HBTs) and
static flip-flop frequency dividers have been fabricated. An
f<sub>t</sub> and an f<sub>max</sub> of 49 and 62 GHz,
respectively, have been achieved in a device with a 2 x
5-μm<sup>2</sup> emitter. Current-mode logic (CML) was
used to implement static divide-by-two and divide-by-four
circuits. The divide-by-two circuit operated at 15 GHz with
82-mW power dissipation for the single flip-flop. The
divide-by-four circuit operated at 14.5 GHz with a total
chip power dissipation of 444 mW.},
Key = {90035240892}
}
@article{3403466,
Author = {Jensen, J.F. and Mishra, U.K. and Brown, A.S. and Salmon,
L.G. and Delaney, M.J.},
Title = {Ultrahigh speed static and dynamic frequency divider
circuits},
Journal = {Microw. J. (USA)},
Volume = {32},
Number = {3},
Pages = {131 - 2},
Year = {1989},
Keywords = {aluminium compounds;field effect integrated
circuits;frequency dividers;gallium arsenide;high electron
mobility transistors;III-V semiconductors;indium
compounds;integrated logic circuits;MMIC;Schottky gate field
effect transistors;},
Abstract = {The authors describe the design, fabrication and testing of
high speed GaAs MESFET and AlInAs-GaInAs HEMT frequency
divider circuits. GaAs MESFET static frequency dividers
operate at frequencies up to 18 GHz, and GaAs MESFET dynamic
dividers operate at frequencies up to 26.6 GHz. When the
same static divider designs were implemented in
AlInAs-GaInAs HEMT technology, the performance improved to
frequencies up to 25.4 GHz. Electro-optic testing techniques
were used to verify the performance of the GaAs MESFET
dividers},
Key = {3403466}
}
@article{3419258,
Author = {Brown, A.S. and Delaney, M.J. and Singh,
J.},
Title = {The effect of inhibited growth kinetics on GaInAs and AlInAs
alloy and interface quality},
Journal = {J. Vac. Sci. Technol. B, Microelectron. Process. Phenom.
(USA)},
Volume = {7},
Number = {2},
Pages = {384 - 7},
Address = {West Lafayette, IN, USA},
Year = {1989},
url = {http://dx.doi.org/10.1116/1.584756},
Keywords = {aluminium compounds;gallium arsenide;III-V
semiconductors;indium compounds;molecular beam epitaxial
growth;semiconductor epitaxial layers;semiconductor
growth;},
Abstract = {Ga<sub>0.47</sub>In<sub>0.53</sub>As and
Al<sub>0.48</sub>In<sub>0.52</sub>As alloys, lattice matched
to InP substrates, are typically grown under conditions (low
substrate temperature and high V/III flux ratios) which
limit cation surface mobilities. For the (Al,Ga)As system,
the growth of material with low-defect density and good
microscopic surface morphology is dependent on highly mobile
cations which can reach kink sites on the growing surface.
In the (Al,In,Ga)As system, other factors such as the
miscibility gap in the AlInAs phase diagram and the
volatility of InAs component dominate the growth condition
requirements. In order to determine the role kinetic
limitations play in reducing the quality of GaInAs and
AlInAs under `normal' molecular beam epitaxy growth
conditions, epitaxial layers were grown at extremely low
substrate temperatures and high V/III ratios to examine the
sensitivity of materials properties to these growth
conditions},
Key = {3419258}
}
@article{3329494,
Author = {Yu-Peng Hu and Petroff, P.M. and Xueyu Qian and Brown,
A.S.},
Title = {Substrate misorientation effects on the structure and
electronic properties of GaInAs-AlInAs interfaces},
Journal = {Appl. Phys. Lett. (USA)},
Volume = {53},
Number = {22},
Pages = {2194 - 6},
Year = {1988},
url = {http://dx.doi.org/10.1063/1.100280},
Keywords = {aluminium compounds;cathodoluminescence;gallium
arsenide;III-V semiconductors;indium compounds;luminescence
of inorganic solids;molecular beam epitaxial
growth;semiconductor quantum wells;},
Abstract = {The effects of substrate misorientation on the interface
quality of Ga<sub>0.47</sub>In<sub>0.53</sub>As/Al<sub>048</sub>In<sub>0.52</sub>As
quantum well structures grown by molecular beam epitaxy
lattice matched on InP substrates have been investigated.
Transmission electron microscopy and low-temperature (15 K)
cathodoluminescence spectra have been used to characterize
the GaInAs/AlInAs layers and analyze the effects of
nucleation and growth kinetics on the heterojunction
interface quality. The quantum well luminescence line shape
correlates with the presence of compositional fluctuations
in the AlInAs layers and thickness variations of the quantum
wells for structures deposited on misoriented substrates.
Rapid thermal annealing of these samples improves the
quantum well luminescence characteristics},
Key = {3329494}
}
@article{3292053,
Author = {Brown, A.S. and Mishra, U.K. and Henige, J.A. and Delaney,
M.J.},
Title = {The effect of InP substrate misorientation on GaInAs-AlInAs
interface and alloy quality},
Journal = {J. Appl. Phys. (USA)},
Volume = {64},
Number = {7},
Pages = {3476 - 80},
Year = {1988},
url = {http://dx.doi.org/10.1063/1.341482},
Keywords = {aluminium compounds;gallium arsenide;III-V
semiconductors;indium compounds;luminescence of inorganic
solids;photoluminescence;semiconductor epitaxial
layers;semiconductor quantum wells;},
Abstract = {The quality of GaInAs-AlInAs epitaxial layers is found to be
critically dependent on the degree of (100)-InP substrate
misorientation. The alloy quality of both materials is
improved when the substrate is misoriented 4° off the
(100). The heterojunction interface quality as determined by
the full width at half-maximum of quantum-well
photoluminescence is also improved when a substrate
misoriented by 4° is used. A degradation of both alloy
and interface quality as compared to material on (100) InP
is observed when the misorientation is 2°. These effects
are also observed for strained quantum-well
structures},
Key = {3292053}
}
@article{89034180723,
Author = {Mishra, Umesh K. and Jensen, Joseph F. and Brown, April S. and Thompson, M.A. and Jelloian, L.M. and Beaubien, Randall
S.},
Title = {Ultra-high-speed digital circuit performance in 0.2-μm
gate-length AlInAs/GaInAs HEMT technology.},
Journal = {IEEE Electron Device Letters},
Volume = {9},
Number = {9},
Pages = {482 - 484},
Year = {1988},
url = {http://dx.doi.org/10.1109/55.6952},
Keywords = {LOGIC CIRCUITS;MICROWAVE DEVICES;},
Abstract = {The fabrication of fifteen-stage ring oscillators and static
flip-flop frequency dividers with 0.2-μm gate-length
AlInAs/GaInAs HEMT technology is described. The fabricated
HEMT devices within the circuits demonstrated a
g<sub>m</sub> transconductance of 750 mS/mm and a
full-channel current of 850 mA/mm. The measured cutoff
frequency of the device is 120 GHz. The shortest gate delay
measured for buffered-FET-logic (BFL) ring oscillators at
300 K was 9.3 ps at 66.7 mW/gate (fan-out = 1); fan-out
sensitivity was 1.5 ps per fanout. The shortest gate delay
measured for capacitively enhanced logic (CEL) ring
oscillaltors at 300 K was 6.0 ps at 23.8 mW/gate (fan-out =
1) with a fan-out sensitivity of 2.7 ps per fan-out. The CEL
gate delay reduced to less than 5.0 ps with 11.35-mW power
dissipation when measured at 77 K. The highest operating
frequency for the static dividers was 26.7 GHz at 73.1 mW
and 300 K.},
Key = {89034180723}
}
@article{89075010800,
Author = {Mishra, U.K. and Brown, A.S. and Rosenbaum, S.E. and Delaney, M.J. and Vaughn, S. and White, K.},
Title = {Noise performance of submicrometer AlInAs-GaInAs
HEMT's},
Journal = {IEEE Transactions on Electron Devices},
Volume = {35},
Number = {12},
Pages = {2441 -},
Year = {1988},
url = {http://dx.doi.org/10.1109/16.8861},
Keywords = {Semiconducting Aluminum Compounds;Semiconducting Gallium
Compounds;Millimeter Waves;},
Abstract = {Record DC and RF performance of AlInAs-GaInAs lattice
matched to InP HEMTs (high-electron-mobility transistors)
with nominally 0.2- and 0.1-μm gate lengths have been
achieved. The devices were fabricated on material grown by
MBE (molecular-beam epitaxy) on Fe-doped InP substrates. The
epitaxial layers consisted of an undoped AlInAs spacer, a
highly doped AlInAs donor layer, an undoped
Schottky-enhancing AlInAs layer, and, finally, a highly
doped GaInAs layer contact layer. 50-μm-wide devices with
0.2- and 0.1-μm-long T-gates were fabricated. The
0.2-μm gate-length devices were tested at V-band. The
single-state amplifier (waveguide to waveguide with no
correction) exhibited a minimum noise figure F<sub>min</sub>
of 1.8 dB with an associated gain 7.5 dB at 63.0 GHz. This
translates to an amplifier noise measure of 2.10 dB. The
corresponding device performance was a minimum noise figure
of 1.4 dB with an associated gain of 8.5 dB. This
corresponds to a device noise measure of 1.6
dB.},
Key = {89075010800}
}
@article{89054230190,
Author = {Mishra, Umesh K. and Brown, April S.},
Title = {InGaAs/AlInAs HEMT technology for millimeter wave
applications},
Journal = {Technical Digest - GaAs IC Symposium (Gallium Arsenide
Integrated Circuit)},
Pages = {97 - 100},
Address = {Nashville, TN, USA},
Year = {1988},
url = {http://dx.doi.org/10.1109/GAAS.1988.11032},
Keywords = {Semiconducting Gallium Compounds;Molecular Beam
Epitaxy;Transistors;Integrated Circuits;Millimeter
Waves;},
Abstract = {AlInAS-GaInAs modulation-doped structures grown by MBE
(molecular-beam epitaxy) on InP have demonstrated excellent
electronic and optical properties. Extremely high sheet
charge densities (n<sub>s</sub> ~5 × 10<sup>18</sup>
cm<sup>-3</sup>) and room temperature mobilities (μ ~9500
cm<sup>2</sup> V<sup>-1</sup> s<sup>-1</sup>) have been
achieved. 0.1-m-gate-length HEMTs (high-electron-mobility
transistors) have exhibited an f<sub>t</sub> (unity current
gain cutoff frequency) ~170 GHz, whereas single stage
amplifiers using 0.2-μm-gate HEMTs have demonstrated a
minimum noise figure of 0.8 dB and an associated gain of 8.7
dB. Ring oscillators have demonstrated 6-ps switching speeds
and static frequency dividers operated at 26.7 GHz at room
temperature.},
Key = {89054230190}
}
@article{89034180573,
Author = {Jensen, Joseph F. and Mishra, U.K. and Brown, A.S. and Beaubien, R.S. and Thompson, M.A. and Jelloian,
L.M.},
Title = {25 GHz static frequency dividers in AlInAs-GaInAs HEMT
technology.},
Journal = {Digest of Technical Papers - IEEE International Solid-State
Circuits Conference},
Volume = {31},
Pages = {268 - 269},
Address = {San Francisco, CA, USA},
Year = {1988},
Keywords = {SEMICONDUCTING ALUMINUM COMPOUNDS;LOGIC CIRCUITS;},
Abstract = {The authors describe the ultrahigh-speed performance of
static flip-flop divide-by-two circuits implemented in both
buffered FET logic (BFL) and capacitively enhanced logic
(CEL) families utilizing 0.2-μm gate-length
Al<sub>.48</sub>In<sub>.52</sub>As-Ga<sub>.4
7</sub>In<sub>.53</sub>As high-electron-mobility transistors
(HEMT) fabricated on InP substrates. The dividers were
tested on-wafer using a probe station at 300°K
temperature. The highest operating frequency at 25.4 GHz was
achieved with a CEL divider. At this frequency the divider
dissipated 63.8 mW. A BFL divider operated at 25.2 GHz with
450 mW power dissipation.},
Key = {89034180573}
}
@article{89095050186,
Author = {Mishra, U.K. and Brown, A.S. and Rosenbaum,
S.E.},
Title = {DC and RF performance of 0.1 μm gate length
Al.48In.52As-Ga.38In.62As
pseudomorphic HEMT's},
Journal = {Technical Digest - International Electron Devices
Meeting},
Pages = {180 - 183},
Address = {San Francisco, CA, USA},
Year = {1988},
url = {http://dx.doi.org/10.1109/IEDM.1988.32784},
Keywords = {Semiconducting Aluminum Compounds;},
Abstract = {The authors report on the epitaxial layer design, device
fabrication, and millimeter-wave performance of
lattice-matched and pseudomorphic AlInAs-GaInAs HEMTs
(high-electron-mobility transistors). The authors fabricated
0.1-μm gate length HEMTs using pseudomorphic
Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.38</sub>In<sub>0.62</sub>As
modulation-doped epitaxial layers and compared them with
lattice-matched Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.47</sub>In<sub>0.53</sub>As
HEMTs. The pseudomorphic HEMTs demonstrated an external
f<sub>T</sub> (current-gain cutoff frequency) of 205 GHz,
which is the first demonstration of a transistor with an
f<sub>T</sub> gt; 200 GHz. The V-band noise figure of an
amplifier built with the lattice-matched, pseudomorphic
HEMTs was 1.3 dB and 1.5 dB, respectively. The associated
gain was 9.5 dB and 8.0 dB, respectively.},
Key = {89095050186}
}
@article{88070099662,
Author = {Mishra, Umesh K. and Brown, A. S. and Jelloian, L. M. and Hackett, L. H. and Delaney, M. J.},
Title = {HIGH-PERFORMANCE SUBMICROMETER ALINAS-GAINAS
HEMT'S.},
Journal = {IEEE Electron Device Letters},
Volume = {9},
Number = {1},
Pages = {41 - 43},
Year = {1988},
url = {http://dx.doi.org/10.1109/55.20407},
Keywords = {SEMICONDUCTING GALLIUM ARSENIDE;SEMICONDUCTING ALUMINUM
COMPOUNDS;SEMICONDUCTING INDIUM COMPOUNDS;},
Abstract = {The performance of long (1. 3- mu m) and short (0. 3- mu m)
gate-length Al//0//. //4//8In//0//. //5//2 As-Ga//0//.
//4//7In//0//. //5//3 high-electron-mobility transistors
(HEMTs) is reported. Transconductances of 465 and 650 mS/mm,
respectively, were achieved. The 0. 3- mu m-long gate-length
device exhibited an f//t greater than 80 GHz. These results
are attributed to the excellent electronic properties of the
AlInAs-GaInAs modulation-doped system.},
Key = {88070099662}
}
@article{89095050346,
Author = {Mishra, U.K. and Jensen, J.F. and Rensch, D.B. and Brown,
A.S. and Pierce, M.W. and McCray, L.G. and Kargodorian, T.V. and Hoefer, W.S. and Kastris, R.E.},
Title = {48 GHz AlInAs/GaInAs heterojunction bipolar
transistors},
Journal = {Technical Digest - International Electron Devices
Meeting},
Pages = {873 - 875},
Address = {San Francisco, CA, USA},
Year = {1988},
url = {http://dx.doi.org/10.1109/IEDM.1988.32948},
Keywords = {Semiconducting Aluminum Compounds;Semiconducting Gallium
Compounds;Band Structure;Molecular Beam Epitaxy;Microwave
Measurements;},
Abstract = {The authors report on the DC and RF performance of
self-aligned Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.47</sub>In<sub>0.53</sub>As
heterojunction bipolar transistors. The properties that make
the AlInAns/GalnAs material system extremely attractive for
heterojunction bipolar transistors are discussed. The
epitaxial layer structure was grown by molecular beam
epitaxy on semi-insulating InP. The device structure is
shown in cross section. A large variety of heterojunction
bipolar transistor devices with different emitter sizes and
with different numbers of emitter fingers have been
fabricated. The common emitter characteristics of a single
5-μm × 5-μm emitter are reported.},
Key = {89095050346}
}
@article{89054230617,
Author = {Mishra, Umesh K. and Brown, April S. and Rosenbaum, S.E. and Hooper, C.E. and Pierce, M.W. and Delaney, M.J. and Vaughn,
S. and White, K.},
Title = {Microwave performance of AlInAs-GaInAs HEMT's with 0.2- and
0.1-μm gate length},
Journal = {IEEE Electron Device Letters},
Volume = {9},
Number = {12},
Pages = {647 - 649},
Year = {1988},
url = {http://dx.doi.org/10.1109/55.20424},
Keywords = {Molecular Beam Epitaxy;Semiconducting Indium
Compounds;Amplifiers;},
Abstract = {The millimeter-wave performance is reported for
Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.47</sub>In<sub>0.53</sub>As
high-electron-mobility transistors (HEMTs) with 0.2-μm
and 0.1-μm-long gates on material grown by molecular-beam
epitaxy on semi-insulating InP substrates. Devices of
50-μm width exhibited extrinsic transconductances of 800
and 1080 mS/mm, respectively. External f<sub>T</sub>
(maximum frequency of oscillation) of 120 and 135 GHz,
respectively, were measured. A maximum f<sub>T</sub> of 170
GHz was obtained from a 0.1 × 200-μm<sup>2</sup>
device. A minimum noise figure of 0.8 dB and associated gain
of 8.7 dB were obtained from a single-stage amplifier at
frequencies near 63 GHz.},
Key = {89054230617}
}
@article{3158819,
Author = {Brown, A.S. and Henige, J.A. and Delaney,
M.J.},
Title = {Photoluminescence broadening mechanisms in high quality
GaInAs-AlInAs quantum well structures},
Journal = {Appl. Phys. Lett. (USA)},
Volume = {52},
Number = {14},
Pages = {1142 - 3},
Year = {1988},
url = {http://dx.doi.org/10.1063/1.99185},
Keywords = {aluminium compounds;gallium arsenide;III-V
semiconductors;indium compounds;luminescence of inorganic
solids;photoluminescence;semiconductor superlattices;},
Abstract = {GaInAs-AlInAs quantum well structures have been analyzed by
low-temperature photoluminescence. The photoluminescence
linewidth (full width at half-maximum) of thicker quantum
wells (>10 nm) grown directly on AlInAs buffer layers
shows that an inverse relationship exists between interface
quality and AlInAs alloy quality in agreement with the
theoretical analysis of J. Singh, S. Dudley, B. Davies, and
K.K. Bajaj [J. Appl. Phys. <b>60</b>, 3167 (1986)]. Thinner
wells show much improved luminescence properties due to a
growth of previous wells},
Key = {3158819}
}
@article{3189252,
Author = {Brown, A.S. and Mishra, U.K. and Henige, J.A. and Delaney,
M.J.},
Title = {The impact of epitaxial layer design and quality on
GaInAs/AlInAs high-electron-mobility transistor
performance},
Journal = {J. Vac. Sci. Technol. B, Microelectron. Process. Phenom.
(USA)},
Volume = {6},
Number = {2},
Pages = {678 - 81},
Address = {Los Angeles, CA, USA},
Year = {1988},
url = {http://dx.doi.org/10.1116/1.584389},
Keywords = {aluminium compounds;gallium arsenide;high electron mobility
transistors;III-V semiconductors;indium compounds;semiconductor
epitaxial layers;},
Abstract = {Ga<sub>0.47</sub>In<sub>0.53</sub>As-Al<sub>0.48</sub>In<sub>0.52</sub>As
high-electron-mobility transistors (HEMT's) exhibit high
transconductance and gain because of the high conductivities
achievable in the structures. The effect of epitaxial layer
design (spacer thickness and active channel thickness) on
conductivity is examined. Device characteristics are
examined as a function of active channel thickness. Reduced
output conductance is observed for a 200 Å channel,
but with a reduced transconductance},
Key = {3189252}
}
@article{3287288,
Author = {Jensen, J.F. and Mishra, U.K. and Brown, A.S. and Beuabien,
R.S. and Thompson, M.A. and Jelloian, L.M.},
Title = {25 GHz static frequency dividers in AlInAs-GaInAs HEMT
technology},
Journal = {1988 IEEE International Solid-State Circuits Conference.
Digest of Technical Papers. 31st ISSCC. First
Edition},
Pages = {268 - 9},
Address = {San Francisco, CA, USA},
Year = {1988},
Keywords = {aluminium compounds;field effect integrated
circuits;flip-flops;frequency convertors;gallium
arsenide;high electron mobility transistors;III-V
semiconductors;indium compounds;integrated logic
circuits;},
Abstract = {The authors describe the ultrahigh-speed performance of
static flip-flop divide-by-two circuits implemented in both
buffered FET logic (BFL) and capacitatively enhanced logic
(CEL) families utilizing 0.2-μm gate-length
Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.47</sub>In<sub>0.53</sub>As
high-electron-mobility transistors (HEMT) fabricated on InP
substrates. The dividers were tested on-wafer using a probe
station at 300 K temperature. The highest operating
frequency at 25.4 GHz was achieved with a CEL divider. At
this frequency the divider dissipated 63.8 mW. A BFL divider
operated at 25.2 GHz with 450 mW power dissipation},
Key = {3287288}
}
@article{3132929,
Author = {Mishra, U.K. and Brown, A.S. and Jelloian, L.M. and Hackett,
L.H. and Delaney, M.J.},
Title = {High performance submicrometer AlInAs-GaInAs
HEMTs},
Journal = {IEEE Trans. Electron Devices (USA)},
Volume = {ED-34},
Number = {11},
Pages = {2358 -},
Address = {Santa Barbara, CA, USA},
Year = {1987},
Keywords = {aluminium compounds;gallium arsenide;high electron mobility
transistors;III-V semiconductors;indium compounds;molecular
beam epitaxial growth;semiconductor epitaxial
layers;},
Abstract = {The performance of long-gate and short-gate
Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.47</sub>In<sub>0.53</sub>As
HEMTs fabricated in high-quality MBE (molecular-beam-epitaxially)-grown
material is discussed. The device structures were grown
lattice-matched to semi-insulating InP substrates. The
typical layer consists of an AlInAs buffer, followed by an
undoped GaInAs channel, a thin undoped AlInAs space, a doped
AlInAs donor layer, an undoped AlInAs barrier layer,
followed finally by an n<sup>+</sup> GaInAs cap layer. The
two epitaxial layer designs (wafers <i>A</i> and <i>B</i>)
investigated to date differed only in the GaInAs channel
thickness, 80 nm for wafer <i>A</i> and 40 nm for wafer
<i>B</i>. Both the wafers exhibited sheet charge density
<i>n</i><sub>s</sub> and mobility values of approximately
3.5×10<sup>12</sup> cm<sup>-2</sup> and 9500
cm<sup>2</sup> V<sup>-1</sup> S<sup>-1</sup> at 300 K and
3×10<sup>12</sup> cm<sup>-2</sup> and 30000
cm<sup>2</sup> V<sup>-1</sup> S<sup>-1</sup> at 77 K.
Devices with 1.3-μm gate length were fabricated on both
wafers. Transconductances of over 465 mS/mm at 300 K were
measured on several devices on both wafers},
Key = {3132929}
}
@article{87050067453,
Author = {Palmateer, L. F. and Tasker, P. J. and Itoh, T. and Brown,
A. S. and Wicks, G. W. and Eastman, L. F.},
Title = {MICROWAVE CHARACTERISATION OF 1 mu m-GATE Al//0//.
//4//8In//0//. //5//2As/Ga//0//. //4//7 In//0//.
//5//3As/InP MODFETs.},
Journal = {Electronics Letters},
Volume = {23},
Number = {1},
Pages = {53 - 55},
Year = {1987},
Keywords = {MICROWAVE DEVICES;SEMICONDUCTING ALUMINUM COMPOUNDS -
Applications;SEMICONDUCTING GALLIUM COMPOUNDS -
Applications;SEMICONDUCTING INDIUM COMPOUNDS -
Applications;},
Abstract = {We report microwave characterisation of nominally 1 mu
m-gate Al//0//. //4//8In//0//. //5//2As/Ga//0//. //4//7
In//0//. //5//3As (lattice-matched to InP) modulation-doped
field-effect transistors (MODFETs). The Al//0//.
//4//8In//0//. //5//2As/Ga//0//. //4//7 In//0//. //5//3As
MODFETs have room-temperature extrinsic transconductances as
high as 250mS/mm. A room-temperature unity-current-gain
cutoff frequency (f//T) of 22 GHz and an f//m//a//x of 35
GHz were measured for a 1. 2 mu m-gate MODFET.},
Key = {87050067453}
}
@article{3157433,
Author = {Mishra, U.K. and Jensen, J.F. and Brown, A.S. and Beaubien,
R.S. and Jelloian, L.M.},
Title = {Ultra-high speed AlInAs-GaInAs HEMT technology},
Journal = {1987 International Electron Devices Meeting, IEDM. Technical
Digeset (Cat. No.87CH2515-5)},
Pages = {879 - 80},
Address = {Washington, DC, USA},
Year = {1987},
Keywords = {aluminium compounds;field effect integrated circuits;gallium
arsenide;high electron mobility transistors;III-V
semiconductors;indium compounds;},
Abstract = {The authors report on the ultrahigh-speed performance of
15-stage ring oscillators utilizing 0.2-μm gate length
Al<sub>0.48</sub>In<sub>0.52</sub>As-Ga<sub>0.47</sub>In<sub>0.53</sub>As
HEMTs (high-electron-mobility transistors) fabricated on InP
substrates. The AlInAs-GaInAs modulation-doped system is
extremely attractive for high-speed digital and analog
applications. Fifteen-stage ring oscillators were fabricated
using both buffered FET logic (BFL) and capacitively
enhanced logic (CEL) schemes and their performance was
measured at room temperature (300 K). The shortest gate
delay measured for BFL was 9.26 ps (fanout=1) with 66.7
mW/gate power dissipation. The shortest CEL gate delay was
7.21 ps (fanout=1) at 24.5 mW. The measured fanout,
sensitivities for BFL and CEL are 1.5 ps and 2.7 ps per
fanout respectively. As expected, CEL gates are faster than
BFL gates at low fanout, but CEL is more sensitive to fanout
because its output is not buffered},
Key = {3157433}
}
@article{3157573,
Author = {Mishra, U.K. and Beaubien, R.S. and Delaney, M.J. and Brown,
A.S. and Hackett, L.H.},
Title = {Low noise 0.1-μm GaAs MESFETS by MBE},
Journal = {Proceedings IEEE/Cornell Conference on Advanced Concepts in
High Speed Semiconductor Devices and Circuits (Cat.
No.87CH2526-2)},
Pages = {177 - 89},
Address = {Ithaca, NY, USA},
Year = {1987},
Keywords = {III-V semiconductors;molecular beam epitaxial
growth;Schottky gate field effect transistors;semiconductor
epitaxial layers;},
Abstract = {Demonstrates that by applying proper scaling techniques,
high-performance 0.1-μm-gate-length GaAs MESFETs can be
routinely fabricated. The noise performance of these devices
compares favorably with that of state-of-the-art HEMT
structures. The performance is limited at the present time
by the parasitic device elements, namely, the source
resistance, gate resistance, drain resistance, and output
conductance. It is clear that using T-gate structures and
further optimization of the epitaxial profiles will address
these issues in the future},
Key = {3157573}
}
@article{88040055373,
Author = {Mishra, U. K. and Brown, A. S. and Jelloian, L. M. and Hackett, L. H. and Delaney, M. J.},
Title = {HIGH PERFORMANCE SUBMICROMETER ALINAS-GAINAS
HEMT'S.},
Journal = {IEEE Transactions on Electron Devices},
Volume = {ED-34},
Number = {11},
Pages = {4 -},
Year = {1987},
Keywords = {SEMICONDUCTOR DEVICES, FIELD EFFECT - Fabrication;MOLECULAR
BEAM EPITAXY - Applications;},
Abstract = {The performance of long-gate and short-gate Al//0//.
//4//8In//0//. //5//2As-Ga//0//. //4//7In//0//. //5//3As
HEMTs fabricated on high-quality MBE (molecular-beam-epitaxially)-grown
material is discussed. The device structures were grown
lattice-matched to semi-insulating InP substrates. The
typical layer consisted of an AlInAs buffer, followed by an
undoped GaInAs channel, a thin undoped AlInAs space, a doped
AlInAs donor layer, an undoped AlInAs barrier layer,
followed finally by an n** plus GaInAs cap layer. The two
epitaxial layer designs (wafers A & B) investigated to date
differed only in the GaInAs channel thickness, 80 nm for
wafer A and 40 nm for wafer B. Devices with 1. 3- mu m gate
length were fabricated on both wafers. Transconductances of
over 465 mS/mm at 300 K were measured on several devices on
both wafers. There was no strong correlation between the
channel thickness and the I-V characteristics. Devices with
approximately 0. 30- mu m gate length were fabricated on
wafer A. They exhibited transconductances of over 650 mS/mm
at room temperature. The maximum drain current density was
approimately 600 mA/mm which is twice the current density
obtainable from single heterojunction AlGaAs-GaAs devices.
This predicts a high fan-out capability for AlInAs-GaInAs
HEMTs.},
Key = {88040055373}
}
@article{88080117571,
Author = {Mishra, U. K. and Beaubien, R. S. and Delaney, M. J. and Brown, A. S. and Hackett, L. H.},
Title = {LOW NOISE 0. 1- mu m GaAs MESFETS BY MBE.},
Pages = {177 - 189},
Address = {Ithaca, NY, USA},
Year = {1987},
Keywords = {SEMICONDUCTOR DEVICES, FIELD EFFECT - Noise;SEMICONDUCTING
GALLIUM ARSENIDE - Applications;MOLECULAR BEAM EPITAXY -
Applications;},
Abstract = {It is demonstrated that by applying proper scaling
techniques, high-performance 0. 1- mu m-gate-length GaAs
MESFETs can be routinely fabricated. The noise performance
of these devices compares favorably with that of
state-of-the-art HEMT structures. The performance is limited
at the present time by the parasitic device elements,
namely, the source resistance, gate resistance, drain
resistance, and output conductance. It is clear that using
T-gate structures and further optimization of the epitaxial
profiles will address these issues in the
future.},
Key = {88080117571}
}
@article{3011865,
Author = {Griem, H.T. and Hsieh, K.H. and D'Haenens, I.J. and Delaney,
M.J. and Henige, J.A. and Wicks, G.W. and Brown,
A.S.},
Title = {Molecular-beam epitaxial growth and characterization of
strained GaInAs/AlInAs and InAs/GaAs quantum well
two-dimensional electron gas field-effect
transistors},
Journal = {J. Vac. Sci. Technol. B, Microelectron. Process. Phenom.
(USA)},
Volume = {5},
Number = {3},
Pages = {785 - 91},
Address = {Cambridge, MA, USA},
Year = {1987},
url = {http://dx.doi.org/10.1116/1.583751},
Keywords = {aluminium compounds;carrier mobility;gallium arsenide;high
electron mobility transistors;III-V semiconductors;indium
compounds;molecular beam epitaxial growth;semiconductor
growth;semiconductor superlattices;},
Abstract = {Defect free strained layer epitaxy opens possibilities for
further improvement on the quantum well two-dimensional
electron gas (TEG) structures grown using the GaInAs/AlInAs
on InP materials system. Increased freedom with composition
allows for optimizing certain properties of the structure,
such as, the conduction edge discontinuity which controls
the maximum sheet concentration (<i>n</i><sub>s</sub>); and
the electron effective mass which influences the speed of
the structure. These enhancements can be made, respectively,
by increasing the Al concentration in the AlInAs and/or by
decreasing the Ga concentration in the GaInAs. The maximum
amount of strain which can be incorporated into the
unrelaxed material sets an upper limit on the compositional
tolerances. The tolerances will be shown to be large for the
AlInAs and the active TEG GaInAs region. The compositions
are obtained using the intensity oscillations observed in
the reflective high-energy electron diffraction (RHEED)
specular beam during growth of GaAs, AlAs, and subsequently
GaInAs and AlInAs on GaAs. X-ray rocking curves and
photoluminescence (PL) are used to verify the calibrations
for growths on InP. The dependency of the mobility on strain
is shown. In As/GaAs superlattice quantum well TEG
structures were grown and characterized. Exceptionally high
Si doping levels roughly 20 times the maximum obtained with
Al<sub>0.25</sub>Ga<sub>0.75</sub>As have been achieved with
lattice matched AlInAs},
Key = {3011865}
}
@article{2860841,
Author = {Brown, A.S. and Itoh, T. and Wicks, G. and Eastman,
L.F.},
Title = {Si diffusion in GaInAs-AlInAs high-electron-mobility
transistor structures},
Journal = {J. Appl. Phys. (USA)},
Volume = {60},
Number = {10},
Pages = {3495 - 8},
Year = {1986},
url = {http://dx.doi.org/10.1063/1.337600},
Keywords = {aluminium compounds;diffusion in solids;gallium
arsenide;Hall effect;high electron mobility
transistors;III-V semiconductors;indium compounds;secondary
ion mass spectra;semiconductor doping;silicon;},
Abstract = {Secondary-ion-mass spectrometry, Hall-effect measurements,
and DC <i>I</i>-<i>V</i> characteristics of 1-μm
Ga<sub>0.47</sub>In<sub>0.53</sub>As-Al<sub>0.48</sub>In<sub>0.52</sub>As
high-electron mobility transistor structures indicate that
significant diffusion of Si can occur in these layers. The
source of the Si is both the intentional Si used for
modulation doping of the devices, and Si which is an
unintentional impurity in the Fe-doped InP substrates on
which the layer is grown. Preannealing and polishing the
substrates can lessen the effect},
Key = {2860841}
}
@article{2729119,
Author = {Itoh, T. and Brown, A.S. and Camnitz, L.H. and Wicks, G.W. and Berry, J.D. and Eastman, L.F.},
Title = {Depletion- and enhancement-mode Al0.48In0.52As/Ga0.47In0.53As
modulation-doped field-effect transistors with a recessed
gate structure},
Journal = {Gallium Arsenide and Related Compounds 1985. Proceedings of
the Twelfth International Symposium},
Pages = {571 - 6},
Address = {Karuizawa, Japan},
Year = {1986},
Keywords = {aluminium compounds;gallium arsenide;high electron mobility
transistors;III-V semiconductors;indium compounds;},
Abstract = {Depletion- and enhancement-mode Al<sub>0.48</sub>In<sub>0.52</sub>As/Ga<sub>0.47</sub>In<sub>0.53</sub>As
modulation doped field effect transistors with 1 μm gate
length have been successfully fabricated by employing a
recessed gate structure and an undoped Al<sub>0.48</sub>In<sub>0.52</sub>As
top layer beneath the gate metal. The fabricated devices
exhibited good DC characteristics with a high
transconductance and a complete pinch-off characteristic.
For both depletion- and enhancement-mode devices, the
transconductances of 250 mS/mm and 300 mS/mm have been
measured at 300K and 77K, respectively},
Key = {2729119}
}
@article{87100161213,
Author = {Griem, H. T. and Hsieh, K. H. and D'Haenens, I. J. and Delaney, M. J. and Henige, J. A. and Wicks, G. W. and Brown,
A. S.},
Title = {CHARACTERIZATION OF STRAINED GaInAs/AlInAs QUANTUM WELL
TEGFETS GROWN BY MOLECULAR BEAM EPITAXY.},
Journal = {Journal of Crystal Growth},
Volume = {81},
Number = {1-4},
Pages = {383 - 390},
Year = {1986},
url = {http://dx.doi.org/10.1016/0022-0248(87)90421-0},
Keywords = {MOLECULAR BEAM EPITAXY;SEMICONDUCTING GALLIUM
COMPOUNDS;},
Abstract = {Defect free strained layer epitaxy opens possibilities for
further improvement on the quantum well two-dimensional
electron gas FET (TEGFET) structures grown using the
GaInAs/AlInAs on InP materials system. Increased freedom
with composition allows for optimizing certain properties of
the structure, such as, the conduction edge discontinuity
which controls the maximum sheet concentration (n//s); and
the electron effective mass which influences the speed of
the structure. These enhancements can be made, respectively,
by increasing the Al concentration in the AlInAs and/or by
decreasing the Ga concentration in the GaInAs. The maximum
amount of strain which can be incorporated into the
unrelaxed material sets an upper limit on the compositional
tolerances. The tolerances are large for the AlInAs and the
active TEG GaInAs region. The compositions are obtained
using the intensity oscillations observed in the reflection
high energy electron diffraction (RHEED) specular beam
during growth of GaAs, AlAs, and subsequently GaInAs and
AlInAs on GaAs. X-ray rocking curves and photoluminescence
(PL) are used to verify the calibrations for growths on
InP.},
Key = {87100161213}
}
@article{2933461,
Author = {Mishra, U.K. and Beaubien, R.S. and Delaney, M.J. and Brown,
A.S. and Hackett, L.H.},
Title = {MBE grown GaAs MESFETs with ultra-high gm and
fT},
Journal = {International Electron Devices Meeting 1986. Technical
Digest (Cat. No.86CH2381-2)},
Pages = {829 - 31},
Address = {Los Angeles, CA, USA},
Year = {1986},
Keywords = {gallium arsenide;III-V semiconductors;molecular beam
epitaxial growth;Schottky gate field effect
transistors;solid-state microwave devices;},
Abstract = {The authors report on the design, fabrication and test
performance of GaAs MESFETs with 0.1-μm gate length. The
devices were fabricated on epitaxial material grown by
molecular beam epitaxy (MBE) on a Riber 2300 system. The
main features of the design are discussed},
Key = {2933461}
}
@article{2716244,
Author = {Brown, A.S. and Wicks, G.W. and Eastman,
L.F.},
Title = {Mn redistribution in doped GaInAs},
Journal = {J. Vac. Sci. Technol. B, Microelectron. Process. Phenom.
(USA)},
Volume = {4},
Number = {2},
Pages = {543 - 4},
Address = {Minneapolis, MN, USA},
Year = {1986},
url = {http://dx.doi.org/10.1116/1.583424},
Keywords = {electromigration;gallium arsenide;III-V semiconductors;impurity
distribution;indium compounds;secondary ion mass
spectra;semiconductor epitaxial layers;},
Abstract = {Summary for only given. The authors discuss some aspects of
the diffusion behavior of Mn in the presence of electric
fields. Impurity profiles were measured by using secondary
ion mass spectrometry (SIMS). No matrix effects exist for Mn
detection in either <i>p</i>- or <i>n</i>-type GaInAs, so
the data were interpreted in a straightforward manner by
comparison with ion-implanted standards},
Key = {2716244}
}
@article{85070089648,
Author = {Brown, A. S. and Palmateer, S. C. and Wicks, G. W. and Eastman, L. F. and Calawa, A. R.},
Title = {BEHAVIOR OF UNINTENTIONAL IMPURITIES IN Ga//0//.
//4//7In//0//. //5//3As GROWN BY MBE.},
Journal = {Journal of Electronic Materials},
Volume = {14},
Number = {3},
Pages = {367 - 378},
Year = {1985},
Keywords = {SEMICONDUCTOR MATERIALS - Impurities;MOLECULAR CRYSTALS -
Epitaxial Growth;SEMICONDUCTING INDIUM COMPOUNDS - Charge
Carriers;MOLECULAR BEAMS;},
Abstract = {A number of factors contribute to the high n-type background
carrier concentration (high 10**1**5 to low 10**1**6 cm**
minus **3) measured in MBE Ga//0//. //4//7In//0//. //5//3As
lattice-matched to InP. The results of this study indicate
that the outdiffusion of impurities from InP substrates into
GaInAs epitaxial layers can account for as much as
two-thirds of the background carrier concentration and can
reduce mobilities by as much as 40%. These impurities and/or
defects can be gettered at the surfaces of the InP by heat
treatment and then removed by polishing. The GaInAs
epitaxial layers grown on the heat-treated substrates have
significantly improved electrical properties. Hall and SIMS
measurements indicate that both donors and acceptors
outdiffuse into the epitaxial layers during growth resulting
in heavily compensated layers with reduced mobilities. The
dominant donor species was idenfified by SIMS as Si, and the
dominant acceptors as Fe, Cr and Mn.},
Key = {85070089648}
}
@article{2759081,
Author = {Itoh, T. and Brown, A.S. and Camnitz, L.H. and Wicks, G.W. and Berry, J.D. and Eastman, L.F.},
Title = {A recessed gate Al0.48In0.52As/Ga0.47In0.53As
modulation doped field effect transistor},
Journal = {Proceedings of the IEEE/Cornell Conference on Advanced
Concepts in High Speed Semiconductor Devices and Circuits
(Cat. No.85CH2173-3)},
Pages = {92 - 101},
Address = {Ithaca, NY, USA},
Year = {1985},
Keywords = {aluminium compounds;gallium arsenide;high electron mobility
transistors;III-V semiconductors;indium compounds;},
Abstract = {1-μm gate Al<sub>0.48</sub>In<sub>0.52</sub>As/Ga<sub>0.47</sub>In<sub>0.53</sub>As
modulation-doped field effect transistors have been
successfully fabricated by using a recessed gate structure
and an undoped Al<sub>0.48</sub>In<sub>0.52</sub>As top
layer beneath the gate metal. The fabricated devices
exhibited good DC characteristics with a high
transconductance and a complete pinch-off characteristic. DC
transconductances of 200 mS/mm and 265 mS/mm have been
measured at 300K and 77K, respectively},
Key = {2759081}
}
@article{2576615,
Author = {Brown, A.S. and Palmateer, S.C. and Wicks, G.W. and Eastman,
L.F. and Calawa, A.R. and Hitzman, C.},
Title = {The heat treatment of Fe-doped InP substrates for the growth
of higher purity Ga0.47In0.53As by
MBE},
Journal = {Semi-Insulating III-V materials},
Pages = {36 - 40},
Address = {Kah-nee-ta, OR, USA},
Year = {1984},
Keywords = {carrier density;carrier mobility;gallium arsenide;Hall
effect;heat treatment;III-V semiconductors;impurities;indium
compounds;iron;molecular beam epitaxial growth;semiconductor
epitaxial layers;semiconductor growth;substrates;},
Abstract = {Impurity outdiffusion, in particular Fe, Mn, and Cr, from
Fe-doped InP into GaInAs epitaxial layers during molecular
beam epitaxy growth can account for as much as two-thirds of
the carrier concentration and can reduce electron mobilities
by as much as 40%. By heating the InP before growth and then
polishing to remove the impurities which have been gettered
at the surface, epitaxial layers with unintentional carrier
concentrations less sensitive to substrate temperature and
higher mobilities can be obtained. Fe-doped InP has been
annealed under pure H<sub>2</sub>, a 92% Ar-8% H<sub>2</sub>
mixture, and a PH<sub>3</sub> ambient to relate the
efficiency of impurity gettering to the ambient heating.
Hall measurements show that the carrier mobilities in
epitaxial layers grown on InP annealed in a pure
H<sub>2</sub> ambient increase more than in those layers
grown on InP heated in an Ar-H<sub>2</sub> mixture. This
suggests that the formation of phosphorus vacancies aids the
surface gettering of outdiffusing impurities},
Key = {2576615}
}
@article{85010008414,
Author = {Brown, A. S. and Wicks, G. W. and Eastman, L. F. and Palmateer, S. C.},
Title = {DEPENDENCE OF ELECTRICAL CHARACTERISTICS OF MBE Ga//0//.
//4//7In//0//. //5//3As PLANAR DOPED BARRIERS ON InP
SUBSTRATES.},
Journal = {Journal of Vacuum Science & Technology B: Microelectronics
Processing and Phenomena},
Volume = {2},
Number = {2},
Pages = {194 - 196},
Address = {Atlanta, GA, USA},
Year = {1983},
url = {http://dx.doi.org/10.1116/1.582777},
Keywords = {SEMICONDUCTING GALLIUM COMPOUNDS;SEMICONDUCTING INDIUM
COMPOUNDS;HEAT TREATMENT;ELECTRIC PROPERTIES;},
Abstract = {The potential barrier height in planar-doped barrier
structures is particularly sensitive to the concentration of
background impurities present in the nominally undoped
regions. MBE grown GaInAs lattice matched to InP typically
has n-type background carrier concentrations in the 10**1**6
cm** minus **3 range. This high level can cause lowering of
the barrier to near zero. By subjecting the InP substrates
to a heat treatment process before growth in order to
inhibit impurity outdiffusion higher purity GaInAs can be
grown and planar-doped barrier devices with more
reproducible characteristics are expected.},
Key = {85010008414}
}
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