First-Principles Study of Boron Diffusion in Silicon

Abstract
In this Letter we investigate boron diffusion as a function of the Fermi-level position in crystalline silicon using ab initio calculations. Based on our results, a new mechanism for B diffusion mediated by Si self-interstitials is proposed. Rather than kick out of B into a mobile channel, we find a direct diffusion mechanism for the boron-interstitial pair for all Fermi-level positions. Our activation energy of 3.53.8 eV, migration barrier of 0.40.7 eV, and diffusion-length exponent of 0.6 to 0.2 eV are in excellent agreement with experiment.