The results of kinetic lattice Monte Carlo simulations of substitutional arsenic diffusion, mediated by lattice vacancies, were presented. Large systems were considered, with 1000 dopant atoms and long-range ab initio interactions to the 18th-nearest neighbor. The diffusivity of each defect species over time was calculated. The concentration of vacancies was made greater than equilibrium concentrations in order to simulate the conditions existing shortly after ion implantation. A previously unreported time dependence in the applicability of the pair diffusion model, even at low temperatures, was demonstrated. Long-range interactions were shown to be of critical importance in kinetic lattice Monte Carlo simulations. When shorter interaction ranges were considered, only clusters which were composed entirely of vacancies formed. An increase in arsenic diffusivity for arsenic concentrations of up to 1019/cm3 was observed, together with a decrease in arsenic diffusivity for higher arsenic concentrations. This was applied to the formation of arsenic-dominated clusters. The effect of vacancy concentration upon diffusivity and clustering was studied, and an increasing vacancy concentration was found to lead to a greater number of clusters, more defects per cluster and a greater vacancy fraction within the clusters.

Vacancy-Assisted Arsenic Diffusion and Time-Dependent Clustering Effects in Silicon. B.P.Haley, N.Grønbech-Jensen: Physical Review B - Condensed Matter and Materials Physics, 2005, 71[19], 195203