Effects of rf-power and working pressure on formation of rutile phase in rf-sputtered TiO2 thin film

Thin TiO2 films have been deposited on glass substrates by a radio-frequency (rf) magnetron sputtering technique. The films were coated under argon atmosphere at three different rf-powers: 80, 100 and 120 W, and three working pressures: 1.0 × 10−2, 2.5 × 10−3 and 1.0 × 10−3 mbar. Film structures were analyzed with XRD. At 100 and 120 W, films coated under low working pressure have developed the rutile phase with the preferred (1 1 0) orientation. However, at 80 W, the films have been observed only in an amorphous phase for all working pressures. This effect could be understood as sputtered TiO2 molecules were more energetic at high rf-powers and encountered fewer collisions at low pressure before deposited onto the substrates. The films have also been annealed at 773 or 873 K. The post-deposition annealing has significantly improved crystallization of the TiO2 films. In this contribution, results on optical and wetting properties of these films are also reported.