By using the plane wave pseudopotential approach, the structure and migration mechanism of an interstitial B pair were deduced. The energy of the proposed configuration was lower, by at least 0.2eV, when compared with other interstitial B pairs. The proposed model, which was equivalent to a B2I2 pair (BmIn = m B-atoms and n Si-atoms occupying m regular sites), migrated in the <110> channel; with the energy barriers between intermediate sites being no greater than 0.1eV and the total energy barrier being 0.6eV between stable sites. Conventional continuum and kinetic Monte Carlo models for the formation of B interstitial clusters did not consider the mobility of the proposed configuration during growth. Its stability to dissociation was expected to have marked consequences in the modeling of transient enhanced B diffusion in Si.

Structure and Diffusion of Interstitial Boron Pairs in Silicon. M.P.Shishkin, M.M.De Souza: Physical Review B, 2004, 69[3], 033201