Behaviors of neutral and charged silicon self-interstitials during transient enhanced diffusion in silicon investigated by isotope superlattices

Abstract

We investigated the contributions of neutral and charged silicon self-interstitials to self- and boron diffusion during transient enhanced diffusion in silicon. We simultaneously observed self- and boron diffusion in silicon using Snati/S28i isotope superlattices. A calculation based on diffusion equations involving {311} defects and boron-interstitial cluster models was employed to reproduce the diffusion profiles in silicon-implanted (intrinsic) and boron-implanted (extrinsic) silicon isotope superlattices, followed by annealing. To investigate the diffusion processes, the time evolution of the silicon self-interstitial profiles during the transient diffusion was simulated. The results directly demonstrate that excess neutral self-interstitials dominantly enhance the self-diffusion during the transient process in the intrinsic conditions, while doubly positively charged self-interstitials dominate the self-diffusion in the extrinsic conditions.