First-principles study of boron diffusion in silicon

In this Letter we investigate boron diffusion as a function of the Fermi-le vel position in crystalline icon using nb 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 di rect diffusion mechanism for the boron-interstitial pair for all Fermi-leve l positions. Our activation energy of 3.5-3.8 eV, migration barrier of 0.4- 0.7 eV, and diffusion-length exponent of -0.6 to -0.2 eV are in excellent a greement with experiment.