Quantification of Electrical Deactivation by Triply Negative Charged Ga Vacancies in Highly Doped Thin GaAs Layers.

We present for the first time a theoretical approach to electrical deactivation by triply negative charged Ga vacancies (V 3- Ga in highly doped thin n-GaAs layers grown by molecular beam epitaxy, and quantify their deactivation under as-grown and annealed conditions. We also show that thinning of n-GaAs epitaxial layers results in low-level electrical deactivation. This effect is apparently caused by the fact that thinning of the doped layers results in lowering of the Fermi energy in the doped layers, and thereby inhibition of the generation of V 3- Ga acceptors. Furthermore, we deduce from the results of this study the thermal equilibrium concentration of V 3- Ga in intrinsic GaAs. The resulting expression is [V 3- Ga (i)] = 5.37 X 10 31 exp(-4.64eV/k B T) cm -3 .