Interaction potentials for vacancy-assisted As diffusion in silicon

A set of interaction potentials for vacancy-assisted As diffusion in silicon have been provided via first-principles pseudopotential calculations. Some important reactions such as As + V reversible arrow AsV, AsV + As reversible arrow As2V, AsV + V reversible arrow AsV2, As + As = As-2 as well as V+V reversible arrow Vt are considered. The results demonstrate that an AsV pair can attract another As due to the binding between the As and the vacancy. It is found that the existence of another As atom nearby greatly reduces the migration barrier for a vacancy moving between the two As atoms. The AsV can also attract another vacancy. The binding force mainly comes from the binding of two vacancies, rather than from that of the AsV pair. The potential energy diagrams obtained provide insight into the dynamical process of As-dopant redistribution in Si and the input for future atomistic diffusion simulations.