Simulation of Boron Diffusion in High-Dose BF2 Implanted Silicon

Abstract

We have simulated the transient enhanced diffusion (TED) of boron (B) after amorphizing BF2 ion implantation in silicon. A unified simulation is done based on the models for B diffusion, for TED by self-interstitial clusters, for B clustering and B precipitation, and for end-of-range (EOR) defects. The simulation overestimates the diffusion using the normal values for the efficiency of EOR defects as a source of self-interstitials. The simulation well reproduces the experimental profiles when the efficiency is reduced so that the defects maintain self-interstitial concentration at thermal equilibrium values. This reduction is attributable to the presence of fluorine at EOR defect sites, which may prevent the release of self-interstitials. In addition, the second peak near the amorphous/crystalline (a/c) interface observed in experimental profiles is reproduced, and the peak is attributed to B precipitates.