Fluorine doped tin oxide thin films were prepared from solutions with high fluorine contents using the spray pyrolysis technique; the resulting films were studied by electron end X-Ray diffraction methods; the resonant nuclear reaction (RNR) method was used to determine the final concentration of fluorine atoms in our films for different doping levels. Also, electrical and optical properties of SnO2:F films were measured and correlated with deposition and structural parameters obtained from X-Ray diffraction and electron microscopy studies.