Reactive sputtering and thermal oxidation effect on transmittance of TiO2 thin films

Titanium dioxide (TiO₂) thin films were grown on SiO2 substrates by DC magnetron sputtering combine with thermal oxidation. A series O₂:Ar ratio from 0:50 to 25:25 and a set of post thermal oxidation at 380~550 oC were tested respectively. The transmittance of titanium dioxide thin films changed with the sputtering parameters and thermal oxidation process in the range. The experiment results showed that reactive gas concentration, sputtering power, sputtering time, film thickness, oxidation temperature and oxidation time had great influence on optical properties of the titanium dioxide thin films. Finally a typical O2:Ar ratio of 20:30~25:25 and a sputtering time of 5 min were selected as the optimized experimental conditions. The optical parameters include: ultraviolet absorption, visible transmittance and the absorption band gaps of the titanium dioxide samples are about 100%, 85% and 4.15 eV.