STOICHIOMETRIC, OPTICAL AND STRUCTURAL PROPERTIES EVOLUTIONS IN TiNx-Oy THIN FILMS PREPARED AT DIFFERENT REACTIVE SPUTTERING TIME

[摘要] Formation of titanium oxynitride at relative low sputtering pressure (≤ 9.98 E-3 Torr) in reactive nitrogen and residual oxygen atmosphere has been observed from previous experiments. In the present study, TiNx-Oy thin film samples with varied thickness, composition and morphology were grown at a fixed low sputtering pressure (8.03E-3 Torr) on glass substrates from 99.99 % purity titanium target, nitrogen gas and vacuum residual oxygen at 200 W. The stoichiometry and thickness variations were studied by Rutherford backscattering (RBS) spectrometry, while X-ray diffractometry (XRD), scanning electron microscopy and UV-Visible spectrophotometry were used to study the structural and optical characteristics of the films. Stoichiometric changes with increase N/Ti and N/O ratios in the films were observed with sputtering time and thickness. Increase in crystallinity with film thickness was seen with preferred orientation at (111) attributed to α-Ti. The films transmission onset red-shift towards visible region with thickness with % Tmax of 14.273 at 574 nm wavelength. The bandgap values varied from 3.72 eV to 2.81 eV with increase in the film thickness.

[学科分类] 生物技术

[关键词] Titanium nitride;Oxynitride;N/Ti ratio;Transmittance;Bandgap energy