The energy barriers to Frenkel pair formation and annihilation in a H-saturated lattice were calculated by using the self-consistent molecular orbitals with linear combination of atomic orbitals technique. The diatomic differential overlap of the energy barriers, which had to be overcome in order to form Frenkel pairs and annihilate them in a H-saturated Si lattice, were partially neglected. The calculations were carried out for the optimized geometries of an ideal Si crystal, a cluster with a vacancy, and a cluster with a vacancy plus various numbers of H atoms. It was shown that, near to a vacancy site, the H was preferentially localized as a second-nearest neighbor. The availability of H near to a vacancy resulted in a marked lowering of the potential barrier to Frenkel-pair annihilation, and the height of the potential barrier was significantly affected by the charge state of the H. The degree of lattice relaxation near to the vacancy was determined as a function of the presence of H, and as a function of the latter’s charge state. The calculations supported a proposed model for the enhanced annealing of vacancy defects in Si with O, and also agreed with experimental data.

V.M.Pinchuk, T.V.Yanchuk, A.N.Nazarov, V.S.Lysenko: Fizika i Tekhnika Poluprovodnikov, 1996, 30[12], 2133-42 (Semiconductors, 1996, 30[12], 1111-5)