Properties of tantalum oxynitride thin films produced by magnetron sputtering: the influence of processing parameters

The main purpose of this work is to present and to interpret the change of structure and physical properties of tantalum oxynitride (TaNxOy) thin films, produced by dc reactive magnetron sputtering, by varying the processing parameters. A set of TaNxOy films was prepared by varying the reactive gases flow rate, using a N2/O2 gas mixture with a concentration ratio of 17:3. The different films, obtained by this process, exhibited significant differences. The obtained composition and the interpretation of X-ray diffraction results, allows to state that, depending on the partial pressure of the reactive gases, the films are: essentially dark grey metallic, when the atomic ratio (N+O)/Ta 1, evidencing the existence of Ta2O5, but with an amorphous structure. These transparent films exhibit refractive indexes, in the visible region, always higher than 2.0. The wear resistance of the films is relatively good. The best behaviour was obtained for the films with (N+O)/Ta = 0.5 and (N+O)/Ta = 1.3.This paper is supported by the Sectoral Operation Programme Human Resources Development (SOP HRD), ID76945 financed from the European Social Fund and by the Romanian Government. This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2011