Diffusion of Ga Vacancies and Si in GaAs

Abstract

AbstractUsing the Si-pair diffusion formalism of Greiner and Gibbons, a new Si diffusion model is developed based on the dominant diffusion species being SiGa+ - VGa- pairs, where VGa is the Ga vacancy. In the model, the unknown parameters are the pair diffusion coefficient (Dp) and the equilibrium constant, which are fitted to the experimental data. Dp is also derived to be equal to one-half the Ga vacancy diffusivity. To verify this relation, an experiment to determine the VGa diffusivity, Dv, is performed. A relation for Dv of the form 0.962 exp(-2.72 eV/kT) cm2/s is obtained, and it is shown that the fitted Dp values are indeed approximately equal to 0.5 Dv.