Modeling of damage enhanced diffusion of implanted boron in silicon

Abstract

Modeling of the damage enhanced diffusion (DED) behavior of implanted boron atoms in silicon based on the experimental results of Powell has been performed. In the experiments, the diffusion of implanted boron was shown to depend on both the implantation dose and the annealing conditions. For lower-dose implantation (2*1015 cm-2), a 900 degrees C/30 minfurnace annealing produced larger diffusion than 15 s rapid thermal annealing. However, in the higher dose case (6*1015 cm-2, the extent of diffusion for these two annealing conditions was reversed. In the case of two-step annealing, there was minimal diffusion observed both for the low-dose and the high-dose cases. In this work, we have related the DED of boron atoms to the excess self-interstitials, which generate mobile boron at the interstitial sites through the kickout mechanism. Both local relaxation and diffusion of self-interstitials are considered. The basic feature of the DED reported by Powell has been successfully reproduced and explained.