Atomic Layer Deposition of High-kappa Dielectric Layers on Ge and III-V MOS Channels

Abstract

Ge and III-V semiconductors are potential high performance channel materials for future CMOS devices. In this work, we have studied Atomic Layer Deposition (ALD) of high-kappa dielectric layers oil Ge and GaAs Substrates. We focus at the effect of the oxidant (H2O, O-3, O-2, O-2 plasma) during gate stack formation. GeO2, obtained by Ge oxidation in O-2 or O-3, is a promising passivation layer. The germanium oxide thickness call be scaled down below I nm, but Such thin layers contain Ge ill oxidation states lower than 4+. Still, electrical results indicate that small amounts of Ge in oxidation states lower than 4+ are not detrimental for device performance. Partial intermixing was observed for high-kappa dielectric and GeO2 or GaAsOx, suggesting possible correlations ill the ALD growth mechanisms oil Ge and GaAs substrates.