Mechanisms of diffusion of boron impurities in SiO2

We report first-principle total-energy calculations that clarify mechanisms of boron diffusion in SiO2. We find that a B atom takes a variety of stable and metastable geometries depending on its charge state. We also find that atomic rearrangements during the diffusion manifest a wealth of bonding feasibility in SiO2 and that the calculated activation energy agrees with the experimental data available. Recombination enhanced diffusion is also proposed.