Kinetic lattice Monte Carlo simulations were made of vacancy-assisted diffusion in silicon. It was shown that the observed temperature dependence of the vacancy migration energy was explained by the existence of three diffusion regimes for divacancies. This was rationalized using an analytical model. In the intermediate temperature regime divacancy dissociation played a key role and an effective migration energy was predicted, as deduced from full ab initio values or those mixed with experimental ones. The exact position of this temperature regime strongly depended upon the vacancy concentration.

Vacancy-Assisted Diffusion in Silicon: a Three-Temperature-Regime Model. D.Caliste, P.Pochet: Physical Review Letters, 2006, 97[13], 135901