The diffusion of P and Sb was used to investigate As self-diffusion, since new P and Sb in-diffusion experiments had revealed the same behavior as had P and Sb interdiffusion experiments; contrary to other published results. Transmission electron microscopy revealed a phase transformation to polycrystalline GaAsP at the surface, under experimental conditions which were similar to those described in the literature. This led to a penetration depth which was much higher than that for P in-diffusion in the absence of the phase transformation. The new diffusion coefficients for P and Sb in-diffusion, at above 900C, were in the same range as the interdiffusion and self-diffusion coefficients for As tracers. It was concluded from this that P and Sb had tracer possibilities for As self-diffusion studies in GaAs. Measurements of the diffusion coefficient under various As-vapour pressures revealed that As self-diffusion was dominated by As self-interstitials. Annealing experiments performed on variously doped samples gave no indication of a Fermi-level effect, and it was concluded that As self-diffusion was governed mainly by neutral defects. At temperatures of between 900 and 1100C, the results for As self-diffusion could be described by:

D (cm2/s) = 75 exp[-4.4(eV)/kT]

The P in-diffusion below 900C exhibited a weaker temperature dependence; indicating a changeover to a different diffusion mechanism.

Phosphorus and Antimony in GaAs as Tracers for Self-Diffusion on the Arsenic Sublattice R.F.Scholz, U.Gösele: Journal of Applied Physics, 2000, 87[2], 704-10