Atomic-scale characterization of boron diffusion in silicon - art. no. 075207

By means of density-functional based tight-binding molecular-dynamics (DF-T BMD) simulations, we investigated the diffusion dynamics of boron in crysta lline silicon. First, the energetics of single B defects in silicon, given by the present model, has been compared to first-principle results, and a d iscussion is provided on the overall accuracy of the DF-TBMD parametrizatio n. We then computed the migration energy in the range 900-1500 K, obtaining a value 0.66 eV, By direct analysis of computer-generated trajectories, we show that B diffusion is a self-interstitial assisted process, displaying no kick-out events. Rather, Si-B pairs clearly diffuse through an interstit ialcy mechanism. We predict a diffusion pre-exponential factor d(B)(o) = 1. 1 x 10(-3) cm(2)/s.