Temperature-accelerated tight-binding molecular dynamics simulations showed that self-interstitial clusters formed from two and three defects were mobile species. In particular, the di-interstitial (I2) cluster was found to diffuse nearly as fast as the single self-interstitial (dumb-bell) over a wide temperature range. In particular, at room temperature I2 was found to diffuse at a rate similar to the dumb-bell, thus making an important contribution to Si self-diffusion at temperatures relevant for Si bulk processing. The simulations also revealed the atomistic mechanisms responsible for the defects' mobility, showing that the I2 cluster must be promoted to a metastable state in which it executes several diffusive events before decaying to a new ground-state configuration equivalent to the initial one.

Diffusion of Small Self-Interstitial Clusters in Silicon - Temperature-Accelerated Tight-Binding Molecular Dynamics Simulations. M.Cogoni, B.P.Uberuaga, A.F.Voter, L.Colombo: Physical Review B, 2005, 71[12], 121203 (4pp)