Spectroscopic ellipsometry (SE), which is a non-destructive and a non-contact optical technique used in characterization of thin films, is widely used to determine thickness, microstructure and optical constants. In this work, the effect of F incorporation on optical properties of SnO2 films grown by ultrasonic spray pyrolysis technique (USP) is presented. The reflections, refractive indices and thicknesses of the films were investigated using room temperature spectroscopic ellipsometry. The optical constants and the thicknesses of the films were fitted according to Cauchy-Urbach model, and ellipsometric angle psi was used as source point for optical characterizations. Besides, transmittance spectra of the films were taken from UV spectrometer, and the optical method was used to determine the band gaps. Also, band tailing resulting from defects or impurities was investigated. From the results obtained from the optical analyses, the application potential of SnO2:F films for solar cell devices was searched. (C) 2010 Elsevier B.V. All rights reserved.