A Simple Model for the Transient, Enhanced Diffusion of Ion-Implanted Phosphorus in Silicon

Abstract

ABSTRACTUnlike As, B as well as P implanted into Si exhibits transient, enhanced diffusion. For example, when P implants are annealed for times of ~1 s at temperatures > 900°C, we observe a large movement of dopant toward the furnace of the Si wafer which is nearly independent of temperature 1050-1200°C. Once the temperature rises above 1200-1250°C the diffusion is similar to that normally observed. We model the experimental results as a transient, enhanced diffusion of a mobile component, about half the total phosphorus implant, distributed deeper in the bulk than the total P distribution. This mobile component may be linked to a large super-saturation of self-interstitials produced by the 50 keV implantation, which are expected to be left deeper in the bulk than the total dopant profile.