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 $\left(V\right)$, As $V$ pairs, ${\mathrm{As}}_{2}V$ complexes, and higher-order ${\mathrm{As}}_n{V}_m$ complexes play distinct roles in the observed dopant deactivation, reactivation, and anomalous diffusion. The latter is mediated by mobile ${\mathrm{As}}_{2}V$ 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.

• Received 7 February 1996

DOI:https://doi.org/10.1103/PhysRevLett.76.4753