SYNTHESIS AND PHYSICOCHEMICAL CHARACTERIZATION OF SILICON OXYNITRIDE THIN-FILMS PREPARED BY RF MAGNETRON SPUTTERING

SiOxNy thin films deposited by rf magnetron sputtering to realize low- loss optical multilayers have been studied. We have analyzed the varia tions of the optical and physicochemical properties of oxynitride laye rs according to the deposition parameters: the gas partial pressures, the rf power, and the target composition. A linear variation of the la yer refractive index as a function of the oxygen partial pressure was observed as well as a strict substitution of O atoms by N atoms. Thank s to IR spectrophotometric analyses, a model of the oxynitride amorpho us structure was proposed and confirmed by Bruggeman and Gained approx imation methods. Finally, the absorption level of the oxynitride layer s was studied by photothermal deflection spectroscopy. (C) 1997 Optica l Society of America.