Properties of titanium oxide film prepared by reactive cathodic vacuum arc deposition

TiO(2) thin films were deposited on a soda-glass substrate as a function of gas pressure (0.1-2.0 Pa) using conventional unfiltered vacuum are deposition (UFA), and also deposited using a macroparticle-filtered are deposition source (FAD). Crystalline structure, microhardness, elastic modulus, and optical properties (transmittance, reflectance, refractive index, extinction coefficient, absorption coefficient, and optical bandgap) were measured or evaluated. All films deposited on unheated substrates were amorphous, and post-annealed films as well as films deposited with in-situ heating were of the crystalline anatase phase. Similar mechanical and optical properties were obtained for the films deposited by UFA over a wide pressure range (0.1-1.0 Pa). After the annealing process, the films became harder, and the extinction coefficient of the film increased. The transmittance and the extinction coefficients of films deposited by FAD were found to be slightly superior to those of films deposited by UFA. The optical bandgap was about 3.25 eV for as-deposited amorphous material prepared by both UFA and FAD as well as for in-situ heated anatase film prepared by FAD. (C) 1999 Elsevier Science S.A. All rights reserved.