Amorphous to polycrystalline phase transition in La₂O₃ films grown on a silicon substrate forming Si-doped La₂O₃ films

We have fabricated La₂O₃ films on a Si substrate without a La-Sr intermixing layer at the La₂O₃/Si interface using a pulsed-laser deposition method. X-ray diffraction data shows only two discernible peaks of the La₂O₃ films: hexagonal La₂O₃ (10-1) and cubic La₂O₃ (222), indicating polycrystalline character. During film growth, the reflection high-energy electron diffraction pattern from the La₂O₃ surface change from an initial column shape to a complicated distributed dot pattern with narrow lines, suggesting possible structural property changes in the La₂O₃ film. The occurrence of a structural transition is confirmed by transmission electron microscopy (TEM), which exhibited a clear crystalline phase change from an initial ~10 nm thick amorphous La₂O₃ film to polycrystalline La₂O₃ on Si. The results of X-ray photoelectron spectroscopy atomic depth profile analysis showed that observation of La-silicate over the whole La₂O₃ film indicating that Si difusses through whole thick La₂O₃ films forming Si-doped La₂O₃ films. Detailed information will be presented.