Nominally undoped GaAsSb/GaAs superlattices were annealed at temperatures between 900 and 1100 °C in a closed quartz ampoule. A strong dependence of the interdiffusion coefficients in the GaAs/GaAsSb superlattices on the arsenic vapor pressure was observed by two independent methods: secondary ion mass spectroscopy, and high-resolution x-ray diffraction using dynamic calculations to extract interdiffusion coefficients. The interdiffusion coefficient was low in the Ga-rich regime where an Arrhenius like dependence with an activation energy of 1.5±0.4 eV and a preexponential factor of 7.1×10−12 cm2 s−1 was found. For the As-rich regime the activation energy was 2.0±0.1 eV and the preexponential factor 7.8×10−9 cm2 s−1.

Interdiffusion experiments with GaAsP/GaAs and GaAsSb/GaAs superlattice samples were performed at various temperatures and arsenic vapor pressures. From the depth-concentration profiles effective diffusion coefficients were calculated. The dependence of these effective diffusion coefficients on the ambient arsenic pressure led to the conclusion that the interdiffusion process is governed by a substitutional-interstitial diffusion mechanism. The good agreement of the effective diffusion coefficients of the GaAsP/GaAs and GaAsSb/GaAs samples with each other and the agreement with arsenic self-diffusion data from the literature is an indication that phosphorus and antimony have good tracer properties to investigate arsenic self diffusion. Comparing our results with sulfur in-diffusion experiments from the literature we conclude that the kick-out mechanism governs self-diffusion on the arsenic sublattice in GaAs. Our results are in contradiction to arsenic self-diffusion experiments which indicated a vacancy mechanism.

Interdiffusion coefficients on the group V sublattice of GaAs were determined in GaAsP/GaAs and GaAsSb/GaAs superlattices. Strained GaAs0.86P0.14/GaAs, GaAs0.8P0.2/GaAs0.975P0.025 and GaAs0.98Sb0.02/GaAs superlattices were annealed between 850 °C and 1100 °C under different arsenic vapor pressures. The diffusion coefficient was measured by secondary ion mass spectroscopy and cathodoluminescence spectroscopy. The interdiffusion coefficient was higher under arsenic-rich conditions than under gallium-rich conditions, pointing to an interstitial-substitutional type of diffusion mechanism.

This paper reviews recent developments in our understanding of self- and impurity diffusion processes in gallium arsenide with special emphasis on incorporating recent gallium isotope diffusion data. Specific diffusion mechanisms for carbon, phosphorus, antimony, and sulfur, which are all substitutionally dissolved on the arsenic sublattice are suggested.

Interdiffusion experiments in GaAs/GaAsP and GaAs/GaAsSb superlattices have been performed at various temperatures and As gas pressures. The analysis of the arsenic pressure dependence of the effective diffusion coefficient revealed that a substitutional-interstitial diffusion mechanism governs the interdiffusion process. Computer simulations were performed to study the profile shape of the annealed samples and the As pressure dependence of the effective diffusion coefficient. Combining these observations it was found that the Frank-Turnbull diffusion mechanism governs the interdiffusion for the GaAs/GaAsP and most likely for the GaAs/GaAsSb superlattice samples. The As pressure dependence of the effective diffusion coefficients measured in interdiffusion experiments is opposite to the published pressure dependence measured in As and P in-diffusion experiments. In principle, the apparently contradicting in- and out-diffusion behavior can be reconciled in terms of a diffusion model which involves arsenic vacancies, fast diffusing arsenic vacancy - phosphorus interstitial complexes and fast diffusing phosphorus interstitials (or the corresponding antimony related defects).

A quantitative determination of the contribution of As self-interstitials to the As self-diffusion coefficient in GaAs has been carried out. Values of the As self-interstitial contributions are deduced from sulfur indiffusion profiles in GaAs, which are simulated based on the kick-out mechanism. Furthermore, the relative contributions of As self-interstitials and of As vacancies are discussed.