Investigations were made of B diffusion in crystalline Si using ab initio calculations. Based on these results, a new mechanism for B diffusion mediated by Si self-interstitials was proposed. Rather than kick-out of B into a mobile channel-interstitial, 1- or 2-step diffusion mechanisms were found for the different charge states. The predicted activation energy of 3.5 to 3.8eV, migration barrier of 0.4 to 0.7eV, and diffusion-length exponent of -0.6 to -0.2eV were in excellent agreement with experiment. Results were also presented for ab initio calculations of the structure and energetics of B-interstitial clusters in Si. It was shown that these first-principles results could be used to create a physical B diffusion model within a continuum simulator which has strongly enhanced predictive power in comparison to traditional diffusion models.

Ab Initio Modeling Study of Boron Diffusion in Silicon. W.Windl, R.Stumpf, X.Y.Liu, M.P.Masquelier: Computational Materials Science, 2001, 21[4], 496-504