Abstract

If an optical film is not fully oxidized, its refractive index will be different from fully oxidized material, and significant optical absorption may result. In order to ensure full oxidation of oxide films, evaporations are frequently carried out in reactive atmospheres containing significant partial pressures of oxygen. SiO_x films provide a convenient system for studying the oxidation state of reactively evaporated films, not only because they are important coating materials,¹ but because of structural models have been developed for this system. In this paper, the degree of oxidation of SiO_x films, prepared by reactive electron-beam evaporation of Si under different partial pressures of oxygen, has been examined by x-ray photoelectron spectroscopy (XPS). The analysis suggests that the silicon in the films is not as fully oxidized as might be expected on the basis of the measured oxygen content.

© 1988 Optical Society of America