Springer Online Journal Archives 1860-2000
Electrical Engineering, Measurement and Control Technology
Abstract We discuss mechanisms of Ga self-diffusion and impurity diffusion in GaAs, and of layer mixing enhancement in GaAs/AlGaAs multiple quantum wells (MQWs). Ga self-diffusion and Ga-Al interdiffusion are governed by the triply negatively charged Ga vacancies, V Ga 3− , under intrinsic and n-doping conditions, and by doubly positively charged Ga self-interstitials, I Ga 2+ , under heavy p-doping conditions. The mechanisms responsible for enhancing MQW mixing are the Fermi-level effect for the n-dopants Si and Te, and the combined effects of the Fermi-level and the dopant diffusion-induced nonequilibrium point defects for the p-dopants Zn and Be. For n-type GaAs the donor Si atoms diffuse primarily also via V Ga 3− . For p-type GaAs the interstitial-substitutional impurities Zn and Be diffuse via the kickout mechanism and induce a supersaturation and an undersaturation in the concentrations of I Ga 2+ , respectively, under indiffusion and outdiffusion conditions.
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