The diffusion dynamics of B in crystalline material were investigated by means of density-functional based tight-binding molecular-dynamics simulations. Firstly, the energetics of single B defects, given by the present model, were compared with first-principles results and the overall accuracy of the density-functional based tight-binding molecular-dynamics parameterization was considered. The migration energy at 900 to 1500K was then estimated; yielding a value of 0.66eV. By means of the direct analysis of computer-generated trajectories, it was shown that B diffusion was a self-interstitial assisted process, with no kick-out events. Instead, Si-B pairs clearly diffused via an interstitialcy mechanism. A pre-exponential factor of 1.1 x 10–3cm2/s was predicted for diffusion.

Atomic-Scale Characterization of Boron Diffusion in Silicon. P.Alippi, L.Colombo, P.Ruggerone, A.Sieck, G.Seifert, T.Frauenheim: Physical Review B, 2001, 64[7], 075207 (4pp)