A study of contamination and damage on Si surfaces induced by dry etching

Damage/contamination effects of dry etching in two different modes, plasma etching (PE) and reactive ion etching (RIE), on silicon surfaces just after oxide etching are discussed. The electrical measurements on aluminium Schottky diodes were used to evaluate the effect of dry processing and various postetch treatments on a Si substrate. The presence of heavy metal contamination of the Si surface as a result of dry etching was confirmed by secondary ion mass spectroscopy and SECCO etch defect decoration. C-t (minority-carrier lifetime) measurements on special guard ring devices were used as indirect evidence of heavy metal contaminants. The quality of a gate oxide grown on Si surfaces after dry-etching conditions was examined through breakdown voltage. Improved device electron mobility was observed for the RIE-exposed Si surface compared to PE, due to the smoother surface after the RIE process