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 GaAs 0.86 P 0.14 /GaAs, GaAs 0.8 P 0.2 /GaAs 0.975 P 0.025 and GaAs 0.98 Sb 0.02 /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.

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 1.5Ϯ0.4 eV and a preexponential factor of 7.1ϫ10 Ϫ12 cm 2 s Ϫ1 was found. For the As-rich regime the activation energy was 2.0Ϯ0.1 eV and the preexponential factor 7.8ϫ10 Ϫ9 cm 2 s Ϫ1 .

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