Atomic layer deposition of TiO2 from tetrakis-dimethylamido-titanium and ozone

Ozone (O₃) was employed as an oxygen source for the atomic layer deposition (ALD) of titanium dioxide (TiO₂) based on tetrakis-dimethyl-amido titanium (TDMAT). The effects of deposition temperature and O₃ feeding time on the film growth kinetics and physical/chemical properties of the TiO₂ films were investigated. Film growth was possible at as low as 75 °C, and the growth rate (thickness/cycles) of TiO₂ was minimally affected by varying the temperatures at 150–225 °C. Moreover, saturated growth behavior on the O₃ feeding time was observed at longer than 0.5 s. Higher temperatures tend to provide films with lower levels of carbon impurities. The film thickness increased linearly as the number of cycles increased. With thicker films and at higher deposition temperatures, surface roughening tended to increase. The as-deposited films were amorphous regardless of the substrate temperatures and there was no change of crystal phase even after annealing at temperatures of 400–600 °C. The films deposited in 0.5 mm holes with an aspect ratio of 3: 1 showed an excellent conformality.