Tuning of Etching Rate by Implantation: Silicon, Polysilicon and Oxide

Abstract

Ion implantation is the mostly used method for semiconductor doping but can also be of interest to change locally the etch rate of silicon and silicon dioxide. Indeed damages induced by ion implantation can increase the etch rate of silicon dioxide by a factor of 200 when etched in vapor HF. Doping species of n or p type increases drastically the etching rate of silicon in HNA. Substitutional boron implanted in silicon can reduce the etch rate of silicon in TMAH from a factor of 200. Etch rate modification by ion implantation can be of interest for the fabrication of buried mask, sacrificial layers and etch stop layers.