Diffusion mechanism of chromium in GaAs

The diffusion of the substitutional Cr atoms (Crs) in GaAs results from the rapid migration of the interstitial atoms (Cri) and their subsequent changeover to occupy Ga sites (or vise versa), a typical substitutional-interstitial-diffusion (SID) process. There are two possible ways for the Cri-Crs changeover to occur: the kick-out mechanism in which Ga self-interstitials are involved, and the dissociative mechanism in which Ga vacancies are involved. The Crs in-diffusion profiles are of characteristic shapes indicating the dominance of the kick-out mechanism, while the Crs out-diffusion profiles are error-function shaped, indicating the dominance of the dissociative mechanism. In this study, an integrated SID mechanism, which takes into account both the kick-out and dissociative mechanisms, is used to analyze Cr diffusion results. Going beyond just qualitative consistency, the Cr in- and out-diffusion features in GaAs are explained on a quantitative basis. It is confirmed that the kick-out mechanism dominates Cr in-diffusion while the dissociative mechanism dominates Cr out-diffusion. Parameters used to fit existing experimental results provided quantitative information on the Ga self-interstitial contribution to the Ga self-diffusion coefficient. The values obtained are consistent with those obtained from a study of Zn diffusion in GaAs, and with available experimentally determined Al-Ga interdiffusion coefficients.

Full Text

Duke Authors

Cited Authors

  • Yu, S; Tan, TY; Gösele, U

Published Date

  • 1991

Published In

Volume / Issue

  • 70 / 9

Start / End Page

  • 4827 - 4836

International Standard Serial Number (ISSN)

  • 0021-8979

Digital Object Identifier (DOI)

  • 10.1063/1.349049

Citation Source

  • SciVal