Reactive direct current magnetron sputtered TiO2 thin films with amorphous to crystalline structures

TiO(2) thin films were deposited on soda-lime glass substrates by reactive direct current magnetron sputtering in a mixture of pure argon and oxygen. The influence of both the deposition time, td, and the post-annealing treatments on the films morphology, composition and structure was analyzed by scanning electron microscopy, ellipsometry, X-ray photoelectrons spectroscopy, X-ray diffraction (XRD) and Raman spectroscopy. Amorphous TiO(2) was obtained for the shortest deposition time, t(d)= 15 min. Increasing t(d) up to 30 min, poorly crystallized anatase and rutile phases were formed together with amorphous TiO(2), as was revealed by complementary XRD patterns and Raman spectra. For longer t(d), the growth of the anatase phase dominates that of the rutile phase. The post-annealing treatment of the films in air at 450 degrees C. induced the complete crystallization of the films leading to mainly anatase films for all the deposition times. All these results show the feasibility to fabricate stoichiometric TiO(2) thin films with amorphous to crystalline structures by means of soft fabrication conditions: low substrate temperature and moderate annealing treatment. (c) 2008 Elsevier B.V. All rights reserved.