Physical modeling of zinc and beryllium diffusion in gallium arsenide
We have examines a large number of the outstanding features associated with Zn and Be diffusion in GaAs and in GaAs/AlGaAs superlattices. All features are qualitatively consistent with the kick-out mechanism which assumes that the group III element self-interstitials govern Ga self-diffusion and Ga-Al interdiffusion. Several features have also been quantitatively modeled via numerical simulations. The Longini mechanism, which assumes that the group III sublattice vacancies govern Ga self-diffusion and Ga-Al interdiffusion, can also be used to explain some of these features, but it contradicts the effects of Zn and Be on superlattice disordering. Combining the assumptions that Zn and Be diffusion is governed by the Longini mechanism and that Ga self-diffusion and Ga-Al interdiffusion are governed by group III element self-interstitials amounts to invoke the kick-out mechanism.
