Preferential growth of thin rutile TiO2 films upon thermal oxidation of sputtered Ti films

Abstract Thin rutile TiO 2 films with (200) preferred orientation were fabricated by thermal oxidation of sputtered Ti metal films on a fused silica substrate. Experimental results indicate that the preferential crystal growth of (200)-oriented TiO 2 is determined by the competition between surface free energy and strain energy. The highly crystalline Ti film with (002) orientation has a greater tendency to promote the growth of (200)-oriented TiO 2 . However, for the amorphous and low crystalline Ti films, orientation of the crystallites evolved in the resulting TiO 2 film tends to be randomly distributed. The extent of preferential crystal growth of TiO 2 (200) plane can be enhanced by decreasing the annealing temperature or the thickness of Ti film.