Structural transition of crystalline Y₂O₃ film on Si(111) with substrate temperature

Crystalline Y₂O₃ films on Si(111) were grown by ionized cluster beam (ICB) deposition in an ultra high vacuum (UHV). The crystallinity of the films deposited at several different temperatures was studied using X-ray diffraction (XRD) and reflection of high-energy electron diffraction (RHEED), and the chemical states of the films was investigated using X-ray photoelectron spectroscopy (XPS). The transformation from monoclinic to cubic structure was observed upon the increase of the substrate temperature from 100 °C to 500 °C. The single crystal cubic structure was obtained at substrate temperatures over 500 °C. The stoichiometry and binding state in the films were gradually changed to a cubic Y₂O₃ structure with the increase of the substrate temperature. The transformation of the film structure from a monoclinic structure to a cubic structure was also observed by post annealing treatment in an oxygen ambient.