Empirical tight-binding calculations were used to make an extensive search for new point defect structures in pure or B-doped material. This involved the use of steepest-descent energy minimization, starting from a random initial structure. This yielded the same set of simple defects (tetrahedral interstitials, split interstitials, simple vacancies) which had already been widely studied in the pure material. But various B interstitials and several new di-interstitials (with and without B) were discovered. A Stillinger-Weber model for Si-B interactions was developed in order to deduce the vibrational entropies of simple point defects. By using the Stillinger-Weber potential, concentration pre-factors were obtained and the usual Arrhenius plots for concentration were reproduced. The theoretical equilibrium concentrations of self-interstitials were consistent with results that had been obtained from Pt and Au in-diffusion experiments. They differed with respect to results derived from oxidation-enhanced or oxidation-retarded diffusion data.

P.B.Rasband, P.Clancy, M.O.Thompson: Journal of Applied Physics, 1996, 79[12], 8998-9011