Room temperature sputtered titanium oxynitride thin films: the influence of oxygen addition

Abstract The nanostructured titanium oxynitride (TiOxNy) thin film was fabricated by a reactive direct current magnetron sputtering method at room temperature. The mechanism of TiOxNy thin film formation depended on the proportion of oxygen and nitrogen gases and their ionization energies. The influence of nitrogen and oxygen gases on microstructural, morphological, and optical properties of nanostructured TiOxNy thin film was investigated by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscope, and ultraviolet-visible spectrophotometer, respectively. The crystalline TiOxNy phase formed when depositing at the O2 flow rate of 0.1 sccm whereas the amorphous TiOxNy phase formed when depositing at the O2 flow rate of 0.2 – 0.4 sccm. In addition, the amorphous TiOxNy phase changed to the titanium dioxide phase when the O2 flow rate was higher than 0.4 sccm. The cross-sectional microstructure and surface morphology of nanostructured TiOxNy thin film exhibited a poorly columnar structure and very smooth surface. The optical bandgap of TiOxNy thin films increased from 1.72 to 3.41 eV when the O2 flow rate was in the range of 0.1 to 1.0 sccm.