First-principles total-energy calculations were used to identify the stable and metastable configurations of interstitial B. The formation energies and ionization levels were calculated for several equilibrium ionic configurations in various possible charge states. In all of the charge states, the ground-state consisted of a B atom which was close to a substitutional site, with a Si self-interstitial nearby. The binding energy of the self-interstitial to substitutional B was rather weak, and of the order of 0.2 to 0.3eV. The ground-state had negative-U properties; in agreement with experiment. Several charge-state dependent metastable configurations of interstitial B were found to be energetically close to the ground state. The role of excess Si interstitials in the activation of B diffusion, and of charge-assisted transport mechanisms in the activation of B, were considered on the basis of formation energies.

First-Principles Calculations of Interstitial Boron in Silicon M.Hakala, M.J.Puska, R.M.Nieminen: Physical Review B, 2000, 61[12], 8155-61