Low loss niobium oxides film deposited by ion beam sputter deposition

Thin films of niobium oxides are deposited by ion beam sputtering with a Ka ufman-type ion source. The deposition rate is function of the oxygen partia l pressure. There is an optimum oxygen pressure at 7 x 10(-5) Torr to depos ite a stoichiometric film. The as-deposited films are amorphous. The optica l parameters, including refractive index, extinction coefficient, and homog eneity, of the oxide films are influenced by post-baking temperature. The s urface morphology measured by an atomic force microscope (AFM) shows that t here is a certain range of optimum baking temperature which yields a smooth film and a good optical quality.