A study of CClF₃/H₂ reactive ion etching damage and contamination effects in silicon

Abstract

A comprehensive characterization of the damage and contamination produced in silicon by CC1F3/H2 reactive ion etching is presented. This highly selective SiO2-to-Si reactive ion etching process unfortunately produces all three of the deleterious damage-contamination layers that can result from dry etching exposure; viz., CC1F3/H2 reactive ion etching produces a residue layer on the Si surface, a permeated layer at the Si near-surface, and a layer of damaged Si. Various post-RIE-exposure, surface-recovery approaches are evaluated in this report. The results indicate that in order to restore the surface to a device-quality state, it is not sufficient to simply eliminate surface contamination. Damage incurred in the silicon bonding must be restored or removed. The latter can be accomplished by suitable treatments such as wet chemical silicon etch or silicide formation.