Atomistic calculations of ion implantation in Si: Point defect and transient enhanced diffusion phenomena

TLDR

A new atomistic approach to Si device process simulation is presented. The method couples a Monte Carlo diffusion code with a binary collision program, modeling vacancy and interstitial recombination, clustering, re‑emission, trapping, and simulates a 40 keV, 5×10¹³ cm⁻² Si implant followed by 815 °C annealing. The simulation shows that implantation damage results in an excess of interstitials forming extended defects, with a total number near the implanted dose, explaining the +1 model’s success and matching TEM observations.

Abstract

A new atomistic approach to Si device process simulation is presented. It is based on a Monte Carlo diffusion code coupled to a binary collision program. Besides diffusion, the simulation includes recombination of vacancies and interstitials, clustering and re-emission from the clusters, and trapping of interstitials. We discuss the simulation of a typical room-temperature implant at 40 keV, 5×1013 cm−2 Si into (001)Si, followed by a high temperature (815 °C) anneal. The damage evolves into an excess of interstitials in the form of extended defects and with a total number close to the implanted dose. This result explains the success of the ‘‘+1’’ model, used to simulate transient diffusion of dopants after ion implantation. It is also in agreement with recent transmission electron microscopy observations of the number of interstitials stored in (311) defects.