Phase development in sputter deposited titanium dioxide

We report the formation of highly oriented rutile titanium dioxide films. Films of a primarily amorphous nature were grown on fused silica by rf reactive sputter deposition using a Ti target and rare gas (Ne or Ar)‐O2 discharges. Post‐deposition annealing was done at 350–1150 °C in air for 60 minute intervals, followed by an air cool. The phase mixture of the as‐deposited films, determined by x‐ray diffraction, was of two types: (I) amorphous + rutile + anatase, or (II) amorphous + rutile. All phases were highly oriented with (110) rutile planes and (101) anatase planes parallel to the substrate. Upon annealing, the amorphous component of films containing no anatase transformed entirely to rutile, even at temperatures where it is possible to form anatase, <800 °C, indicating that anatase requires ‘‘seeds’’ to form. The results of this study clearly demonstrate that the crystal structure of the as‐deposited film determines the development of the rutile phase with post‐deposition annealing.