Mechanism for the Diffusion of Zinc in Gallium Arsenide

Abstract

AbstractThe anomalous shape of the Zn diffusion profile in GaAs has been quantitatively explained. The interchange between interstitial Zn and substitutional Zn is assumed to occur via the Ga vacancies. These vacancies are proposed to be either neutral or singly ionized, depending on the position of the Fermi level. In addition, two physical phenomena are proposed. Substitutional Zn thermally generates interstitial Zn-Ga vacancy pairs and there is pairing between the donor, interstitial Zn and the acceptor, substitutional Zn. This pairing leads to the interstitial Zn diffusivity being a decreasing function of the substitutional Zn concentration. The model is found to be in good agreement with the experimental data.