DENSITY, THICKNESS AND INTERFACE ROUGHNESS OF SIO2 TIO2 AND TA2O5 FILMS ON BK-7 GLASSES ANALYZED BY X-RAY REFLECTION

BK-7 glass with high surface quality and thin oxidic films (SiO2, TiO2, Ta2O5) deposited by ion plating (IP) and reactive evaporation (RE) on BK-7 glass have been characterized by means of X-ray reflectivity. The quantities determined with great precision are the film thickness, the film density and the interface roughness. It turned out that the IP films are more dense and smoother than the corresponding RE films. The ion-plated layers have a thin surface layer on top of the oxide which is reduced in density, whereas for the RE films there is an intermediate layer with an enhanced density between the glass substrate and the oxide.