Optical constants of DC magnetron sputtered titanium dioxide thin films measured by spectroscopic ellipsometry

Optical constants of DC magnetron sputtered TiO2 thin film have been determined by Spectroscopic Ellipsometry in the photon energy range 1.2 to 5.5 eV at room temperature. The measured dielectric-function spectra reveal distinct structures at energies of the E1, E1+Delta1 and E2 critical points are due to interband transitions. The root mean square roughness of the magnetron sputtered TiO2 thin films evaluated by ex-situ atomic force microscopy is 5.8 nm. The Dielectric constant values were found to be substantially lower than those for the bulk TiO2. The dielectric related Optical constants, such as the refractive index, extinction coefficient, absorption coefficient and normal incidence of reflectivity determined from the spectroscopic ellipsometry data are presented and analyzed. The optical constants of the films were also determined using the optical transmittance measurements and the results were discussed.