Influence of working pressure on properties of titanium oxide thin films at room temperature

Titanium oxide thin films were deposited by off-plane filtered cathodic vacuum arc (FCVA) at room temperature as a function of working pressure. The deposition rate decreases with working pressure. The deposited films are amorphous with low residual stress (less than 0.5 GPa) and smooth surface. The film transmittance increases with the increase of working pressure, while the refractive index and extinction coefficient both decrease. Similar behaviors of film properties (e.g., deposition rate and optical properties) are also found in other metal oxides by FCVA, such as zirconium oxide and aluminium oxide. Common features observed in various metal oxides are explained by a model based on ion-gas interactions. The feasibility of these metal oxide thin films as optical coatings is also discussed.