Preparation of aluminum oxide films by ion beam assisted deposition

Aluminum oxide films were prepared by vapor deposition of aluminum and simultaneous irradiation with oxygen ion beam in the energy range of 2–24 keV with an Al/O transport ratio in the range of 0.5–14. The films were formed on Si(100) wafers and glass substrates fixed on a water-cooled holder. Film characterizations were carried out using X-ray photoelectron spectroscopy (XPS) for elemental composition measurements and chemical bonding states, and by X-ray diffraction (XRD) for film crystallization. The XPS spectra of Al 2p1/2 obtained from samples with nearly stoichiometric composition (Al/O∼0.67) showed a peak at ∼74 eV corresponding to the AlO chemical bonding state of the γ phase. The XRD patterns of the films prepared with oxygen ion energy of 20–23 keV showed the crystallization of γ-Al2O3 on both Si(100) wafer and glass substrates. Mechanical and optical properties of the films were also presented in correlation with the deposition conditions.