Publications [#63692] of April S. Brown

Papers Published

1. Kang, Sangbeom and Doolittle, W. Alan and Stock, Stuart R. and Brown, April S., Comparison of AlGaN and GaN grown on various substrates: Step flow growth on LiGaO₂ at low growth temperature, Materials Science Forum, vol. 338 (II (2000), pp. 1499 - 1502, Research Triangle Park, NC, USA
   (last updated on 2007/04/14)

   Abstract:
   AlGaN/GaN heterostructures were grown on LiGaO₂ (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_0.25Ga_0.75N 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.

   Keywords:
   Heterojunctions;Semiconducting aluminum compounds;Semiconducting gallium compounds;Vapor phase epitaxy;Semiconductor growth;Lithium compounds;Sapphire;Morphology;Dislocations (crystals);Crystal symmetry;Crystal lattices;Nitrides;