STRUCTURAL STUDIES OF TUNGSTEN-TITANIUM OXIDE THIN-FILMS

Structural studies of tungsten-titanium oxide thin films. grown on alu mina substrates have been performed on samples prepared by reactive ma gnetron sputtering of a W/Ti alloy (90% W and 10% Ti). Structural chan ges undergone by samples heated at 773 and 1073 K have been studied by using X-ray diffraction and X-ray photoemission techniques. The resul ts, which have been also discussed with the aid of a structural model, indicate that the original amorphous phase transforms by annealing in to a crystalline phase of tungsten oxide with a degree of order depend ing on the annealing temperature. The relationship between titanium an d the structure of the film is discussed in terms of disorder effects induced by the Ti ions in the WO3 lattice. The ordering is ascribed to the segregation of Ti ions toward the surface upon annealing at 1073 K. (C) 1996 Academic Press, Inc.