Low loss niobium oxides film deposited by ion beam sputter deposition

Thin films of niobium oxides are deposited by ion beam sputtering with a Kaufman-type ion source. The deposition rate is function of the oxygen partial pressure. There is an optimum oxygen pressure at 7 × 10^–5 Torr to deposite a stoichiometric film. The as-deposited films are amorphous. The optical parameters, including refractive index, extinction coefficient, and homogeneity, of the oxide films are influenced by post-baking temperature. The surface morphology measured by an atomic force microscope (AFM) shows that there is a certain range of optimum baking temperature which yields a smooth film and a good optical quality.