Roughness and scattering measurements on thin films for UV/VIS applications

An attempt is presented of a systematic experimental approach to the problem of scattering and roughness modification after deposition of an optical thin film. BK 7 substrates with different surface qualities have been coated with evaporated MgF2, LaF3 and magnetron sputtered SiO2 and Nb2O5 films as representatives of low index/high index columnar structured and structureless films, respectively. Investigations by total integrated scattering (TIS) and angle resolved scattering (ARS) at 633 nm and 325 nm as well as atomic force microscopy (AFM) demonstrate the possibility of quite different effects of scattering and roughness modification to occur.