High epitaxial quality Y2O3 high-k dielectric on vicinal Si (001) surfaces

Thin films of Y2O3 were grown by molecular-beam epitaxy on silicon aiming at material with adequate crystal quality for use as high-kappa gate replacements in future transistors. It was found that Y2O3 grows in single-crystalline form on 4degrees misoriented Si(001), due to an in-plane alignment of [110](Y2O2) to the silicon dimer direction. The Y2O3 layers exhibit a low degree of mosaicity, a small proportion of twinning and sharp interfaces. This represents a significant improvement compared to material grown on exact silicon surfaces.