The vacancy in silicon: A critical evaluation of experimental and theoretical results

Recent experimental studies of Shimizu et al. [Phys. Rev. Lett. 98, 095901 (2007)] revealed an activation enthalpy of 3.6 eV for the vacancy contribution to Si self-diffusion. Although this value seems to be in accurate agreement with recent theoretical results, it is at variance with experiments on vacancy-mediated dopant diffusion in Si. In the present study we review results from electronic structure calculations and conclude that the calculations are consistent with an activation enthalpy of 4.5–4.6 eV rather than 3.6 eV for the vacancy contribution to self-diffusion. Moreover, our calculations predict activation enthalpies of 4.45 and 3.81 eV for the vacancy-mediated diffusion of phosphorus and antimony, respectively, in good agreement with the most recent experimental results.