Synthesis of stoichiometric titania films by oxygen ion assistance of growing titanium

Abstract

Reactive ion beam assistance appears to be a useful technique to fabricate optical coatings with the correct stoichiometry. The bombarding ions modify the composition of the growing film principally by the preferential sputtering of the film atoms and by the implantation of the ions themselves. Investigation of these effects is necessary to obtain a desired composition of the coating. In this work, a set of titania films was grown by sputtering from a Ti target and simultaneously bombarding the titanium with a low energy (300 eV) oxygen and argon ion beam. X-ray photoelectron spectroscopy was used to measure the film composition at the surface as-grown and after sputtering for 30 min in situ. In particular, it was seen that the oxygen content increases for an increased oxygen-to-argon flux ratio. In particular, the oxygen content in the film is constant for an oxygen-to-argon flux ratio greater than 0.8. The experimental results for film composition are in agreement with the results obtained by a simple model, developed in this work, to describe the ion assistance phenomena and to estimate the partial sputtering yields.