- Brown, April S. and Losurdo, Maria and Capezzuto, Pio and Bruno, Giovanni and Brown, Terence and May, Gary, Fundamental reactions controlling anion exchange during mixed anion heterojunction formation: Chemistry and kinetics of P-for-As exchange reaction,
Journal of Applied Physics, vol. 99 no. 9
pp. 093510 - [1.2194126] .
(last updated on 2007/04/14)
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.
Reaction kinetics;Surface properties;Epitaxial growth;Superlattices;Semiconducting gallium compounds;X ray diffraction analysis;Ellipsometry;X ray photoelectron spectroscopy;Ion exchange;Chemisorption;