Ab-initio pseudopotential calculations of boron diffusion in silicon

In this work we investigate boron diffusion as a function of the Fermi-level position in crystalline silicon using ab-initio calculations and the nudged elastic band method to optimize diffusion paths. Based on our results, a new mechanism for B diffusion mediated by Si self-interstitials is proposed. We find a two-step diffusion process for all Fermi-level positions, which suggests a kick-out with a directly following kick-in process without extensive B diffusion on interstitial sites in-between. Our activation energy of 3.47 - 3.75 eV and diffusion-length exponent of -0.55 to -0.18 eV are in excellent agreement with experiment.