Tailoring the structural and optical properties of fabricated TiO2 thin films by O2 duty cycle in reactive gas-timing magnetron sputtering

Titanium dioxide (TiO2) thin films were deposited on silicon (100) and glass substrates via conventional reactive sputtering and reactive gas-timing (RGT) sputtering techniques. The duty cycle of supplied O2 gas determined its effect on the properties of the TiO2 films through spectroscopic ellipsometry (SE). With the best triple-layer model for SE fitting, the films' structure and optical properties were analyzed and compared. The high-resolution transmission electron microscope (HR-TEM) showed good agreement with the structure of the SE model, while the grazing-incidence X-ray diffraction (GIXRD) confirmed the crystallinity of the films. The results showed that the duty cycle was a crucial factor in the deposition rate and crystalline phase of the TiO2 films. The optical reflectance (%R) spectra were measured by a UV-VIS-NIR spectrophotometer, representing anti-reflection properties at a specific wavelength related to the duty cycle. Moreover, the omnidirectional optical transmittance (Omni-T) profiles were also determined. The results showed that the transmittances (%T) of TiO2 film near those specific wavelengths were enhanced over the bare glass substrate at a wide angle. In addition, photoelectron spectroscopy (PES) was used to confirm the chemical states and atomic compositions.

Automated summary

Titanium dioxide (TiO2) thin films were deposited on silicon (100) and glass substrates using conventional reactive sputtering and reactive gas-timing (RGT) sputtering techniques. The duty cycle of O2 gas influenced the properties of the TiO2 films, as determined by spectroscopic ellipsometry (SE). The films' structure and optical properties were analyzed and compared using a triple-layer model for SE fitting, high-resolution transmission electron microscope (HR-TEM), and grazing-incidence X-ray diffraction (GIXRD). The deposition rate and crystalline phase of the TiO2 films were found to be influenced by the duty cycle.