Hydrogen Etching Effects During Plasma Doping Processes and Impact on Shallow Junction Formation

Hydrogen etching effects in plasma ion implantation (PII) doping processes alter device structure and implant dopant profile and reduce the retained implant dose. This has particular relevance to the shallow junction devices of ultra large scale integrated circuits (ULSI). Hydrogen etching of semiconductor materials including Si, poly-Si, SiO2, Al, and photoresist films have been investigated. The effects of varying different PII process parameters are presented. The experimental data show that the spontaneous etching by hydrogen radicals enhanced by ion bombardment is responsible for the etching phenomena. A computer simulation is used to predict the as-implanted impurity profile and the retained implant dose for a shallow junction doping when the etching effect is considered.