High-quality epitaxial γ-Al2O3(111) films were grown on a Si(111) substrate covered with a chemically formed 2 nm SiO2 layer using reactive ionized beam deposition. An epitaxial γ-Al2O3 layer was formed at above 800°C, while the films showed polycrystalline below this temperature. Al2O3 films grown on an oxidized Si substrate showed a better crystalline quality, a more fiat surface and a sharper interface than the films grown on a clean Si substrate. A thin SiO2 layer acts as a barrier to prevent a direct reaction of incident Al with Si substrate, the thin layer is consumed during the Al2O3 growth to yield an abrupt Al2O3/Si interface. The role of the thin oxide layer on the film growth and the chemical reactions at the interface during the initial growth of Al2O3 were investigated.
All Science Journal Classification (ASJC) codes
- Materials Chemistry