Complex Dynamical Phenomena in Heavily Arsenic Doped Silicon

Several complex dynamical phenomena have been observed in heavily doped Si, but a comprehensive account of the underlying atomic-scale processes is lacking. We report a wide array of first-principles calculations in terms of which we give such a comprehensive account. In particular, we find that vacancies $(V)$, As V pairs, As₂V complexes, and higher-order AsₙVₘ complexes play distinct roles in the observed dopant deactivation, reactivation, and anomalous diffusion. The latter is mediated by mobile As₂V complexes that form in ``prepercolation'' patches of a very high dopant concentrations and gives rise to fast As clustering at moderate temperatures. Our results are quantitative and in agreement with experimental numbers where available.