Papers Published

1. Tan, T.Y. and Gosele, U. and Yu, S., Point defects, diffusion mechanisms, and superlattice disordering in gallium arsenide-based materials, Crit. Rev. Solid State Mater. Sci. (USA), vol. 17 no. 1 (1991), pp. 47 - 106 .
   (last updated on 2007/04/10)

   Abstract:
   This article reviews recent progress in the understanding of the mechanisms of Ga self-diffusion and impurity diffusion in GaAs, and of the disordering of GaAs/AlGaAs superlattices. Gallium self-diffusion and Al-Ga interdiffusion under intrinsic and n-doping conditions are governed by the triply negatively charged group III sublattice vacancies V_Ga^3-, while under heavy p-doping conditions most likely by the doubly positively charged self-interstitial I_Ga²⁺. The GaAs/AlGaAs superlattice disordering enhancement observed under n-doping by Si or by Te is due to the Fermi-level effect that increases the V_Ga^3- concentration, while the observable or not observable disordering enhancement under p-doping by Zn or by Be is due to the combined effects of the Fermi-level, which increases the I_Ga²⁺ concentration, and the dopant in-diffusion or out-diffusion induced I_Ga²⁺ supersaturation or undersaturation, respectively. In consistency with the Ga self-diffusion mechanism in GaAs, diffusion of the Si donor atoms occupying Ga sites is primarily also governed by V_Ga^3-, while Si acceptor atoms occupying As sites, which is a minority fraction of the total, diffuses via a negatively charged As sublattice point defect species. The interstitial-substitutional p-type dopants Zn and Be diffuse via the kick-out mechanism. Their diffusion induces an I_Ga²⁺ supersaturation and undersaturation, respectively, under the in-diffusion and out-diffusion conditions

   Keywords:
   aluminium compounds;diffusion in solids;gallium arsenide;III-V semiconductors;point defects;reviews;self-diffusion in solids;semiconductor superlattices;