Tracing the incorporation of water in SiO2/SiC structures formed by oxide deposition and thermal oxidation

Abstract

Water vapor incorporation in SiO2 films, obtained by thermal oxidation and/or sputter deposition, on SiC and Si was investigated. Isotopically enriched water was used to allow the 2H (deuterium) quantification and the 18O profiling by nuclear reaction analyses. The incorporation of hydrogen from water vapor in SiO2/SiC and SiO2/Si structures, whose films were deposited by sputtering, occurred mainly in the SiO2 film/substrate interfacial region. Exposure to water vapor led to isotopic exchange between oxygen from the water vapor and oxygen from SiO2 films deposited on SiC and on Si substrates. Longer thermal oxidation times of the SiC prior to the deposition of the SiO2 film led to larger amounts of D incorporated. The thermal growth of a very thin SiO2 film followed by the deposition of SiO2 led to the lowest amounts of D incorporated. These results were correlated with the improvement in the electrical characteristics observed for SiO2/SiC structures obtained by these routes.