- Shaofeng Yu and Gosele, U.M. and Tan, T.Y., A model of Si diffusion in GaAs based on the effect of the Fermi level,
J. Appl. Phys. (USA), vol. 66 no. 7
pp. 2952 - 61 [1.344176] .
(last updated on 2007/04/10)
The authors propose a quantitative model for Si diffusion in GaAs. In this model they incorporate the experimental result that Si is an amphoteric impurity which constitutes a shallow donor when occupying the Ga site, SiGa+, and a shallow acceptor when occupying the As site, SiAs-. At high concentrations SiGa+ and SiAs- coexist. The amphoteric behavior of Si may be viewed as an effect of the Fermi level. They assume that SiGa- and SiAs- diffuse respectively on the Ga and As sublattices. That is, the diffusion of SiGa+ and SiAs- is governed by the variously charged Ga vacancies and As vacancies (or self-interstitials), respectively. The experimentally observed Si diffusivity is concentration dependent which results from the Si amphoteric nature as well as from another effect of the Fermi level, which is its influence on the concentrations of the charged point-defect species. Satisfactory quantitative descriptions of available experimental results are obtained. An analysis of the data on Si diffusion into a Sn-doped GaAs substrate has led us to believe that the previously proposed Si-pair diffusion model may no longer be favored
diffusion in solids;Fermi level;gallium arsenide;III-V semiconductors;impurity electron states;interstitials;silicon;vacancies (crystal);