Optical properties of thin films of SiO$_{x}$ $(x<2)$, obtained by exposure of thermal silicon dioxide in hydrogen plasma

Using the methods of ellipsometry, quantum chemical modeling, and photoluminescent spectroscopy, the optical properties and composition of thin films of thermal silicon oxide processed in a hydrogen electron-cyclotron resonance plasma are studied. It has been established that treatment of films in plasma leads to their depletion in oxygen and the formation of non-stoichiometric oxide SiO$_{x<2}$. By comparing the experimental spectral dependence of the refractive index with the theoretically calculated from the first principles, the values of the parameter $x$ in the obtained SiO$_x$ films are determined. It was shown that an increase in the processing time of thermal SiO$_2$ in hydrogen plasma leads to an increase in the refractive index of the film, as well as the degree of depletion of the film with oxygen. For the studied films, the dependence of the value of the parameter $x$ on the treatment time in a hydrogen plasma is constructed.