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 dea ctivation by triply negative charged Ga vacancies (V-Ga(3-)) in highly doped thin n-GaAs layers grown by molecular beam epitaxy, and quantif y their deactivation under as-grown and annealed conditions. We also s how that thinning of n-GaAs epitaxial layers results in low-level elec trical 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-Ga( 3-) accepters. Furthermore, we deduce from the results of this study t he thermal equilibrium concentration of V(Ga)(3-)in intrinsic GaAs. Th e resulting expression is [V-Ga(3-) (i)] = 5.37 x 10(31) exp(-4.64 eV/ k(B)T)cm(-3).