The neutral vacancy (V) and {V,Hn} complexes, where n = 1 to 4, were studied in various molecular clusters at the approximate ab initio Hartree-Fock level, using post Hartree-Fock corrections in electron correlation. Calculations were made of the equilibrium configurations and electronic structures, dissociation energies, diffusion paths and activation energies. The dissociation energies were compared with those, of other H traps, which had been calculated by using the same level of theory. These traps included substitutional C, interstitial Ti, or {B,H} pairs. The results predicted that the {V,H1} pair should be mobile above room temperature. A part of the barrier for the diffusion of {V,H1} was lower than that for V, due to a mechanism that was analogous to the H-enhanced diffusion of interstitial O in Si. Another part of this barrier was higher than that for V. The effects of this included the possibility of enhanced H diffusion in polycrystalline, as compared with crystalline, Si and suggested a mechanism for the nucleation of platelets in the sub-surface region of plasma-exposed Si.

M.A.Roberson, S.K.Estreicher: Physical Review B, 1994, 49[24], 17040-9