High-quality nanothickness single-crystal Sc2O3 film grown on Si(111)

High-quality single-crystal Sc2O3 films a few nanometer thick have been grown epitaxially on Si (111) despite a huge lattice mismatch. The films were electron-beam evaporated from a Sc2O3 target. Structural and morphological studies were carried out by x-ray diffraction and reflectivity, atomic force microscopy, high-resolution transmission electron microscopy, and medium-energy ion scattering, with the initial epitaxial growth monitored by in situ reflection high-energy electron diffraction. The films have the cubic bixbyite phase with a remarkably uniform thickness and high structural perfection. The film surfaces are very smooth and the oxide/Si interfaces are atomically sharp with a low average roughness of 0.06nm. The films are well aligned with the Si substrate with an orientation relationship of Si(111)‖Sc2O3(111), and an in-plane expitaxy of Si[1¯10]‖Sc2O3[1¯01].