Ion beam sputter deposition of refractory metal oxides

Oxides of hafnium, niobium, tantalum, and zirconium are deposited by ion beam sputtering of the pure metal targets using CO{sub 2} as working gas. The resulting thin films are amorphous, featureless smooth and of excellent adherence to semiconductor substrates. Despite a certain content of carbon they are highly transparent in the visible and near infrared wavelength range as determined by spectroscopic ellipsometry. Their wide range of refractive indices makes them suitable for multilayer optical filter design.