EXPERIMENTAL AND COMPUTER-SIMULATION STUDIES OF DIFFUSION MECHANISMS ON THE ARSENIC SUBLATTICE OF GALLIUM-ARSENIDE

Interdiffusion experiments with GaAsP/GaAs and GaAsSb/GaAs superlattic e samples were performed at various temperatures and arsenic vapor pre ssures. From the depth-concentration profiles effective diffusion coef ficients were calculated. The dependence of these effective diffusion coefficients on the ambient arsenic pressure led to the conclusion tha t the interdiffusion process is governed by a substitutional-interstit ial diffusion mechanism. The good agreement of the effective diffusion coefficients of the GaAsP/GaAs and GaAsSb/GaAs samples with each othe r and the agreement with arsenic self-diffusion data from the literatu re is an indication that phosphorus and antimony have good tracer prop erties to investigate arsenic self diffusion. Comparing our results wi th sulfur in-diffusion experiments from the literature we conclude tha t the kick-out mechanism governs self-diffusion on the arsenic sublatt ice in GaAs. Our results are in contradiction to arsenic self-diffusio n experiments which indicated a vacancy mechanism. (C) 1998 American I nstitute of Physics.