Interdiffusion in superlattices was studied at various temperatures and under various As partial pressures. An analysis of the As pressure-dependence of the effective diffusion coefficient revealed that a substitutional-interstitial diffusion mechanism governed the interdiffusion process. Computer simulations were used to study the profile shapes of annealed samples, and the As pressure dependence of the effective diffusion coefficient. It was found that the Frank-Turnbull diffusion mechanism governed the interdiffusion of these superlattices. The As pressure-dependence of the effective diffusion coefficients, as measured in interdiffusion experiments, was opposite to the reported pressure dependences which had been measured in As and P in-diffusion experiments. The apparently contradictory in-diffusion and out-diffusion behaviors could be reconciled by a diffusion model which involved As vacancies, fast-diffusing As-vacancy plus P-interstitial complexes, and fast-diffusing P interstitials (or the analogous Sb-related defects).

M.Schultz, U.Egger, R.Scholz, O.Breitenstein, P.Werner, U.Gösele, R.Franzheld, M.Uematsu, H.Ito: Defect and Diffusion Forum, 1997, 143-147, 1101-8