Properties of the barium–strontium titanate films deposited onto the silicon substrate by rf cathode sputtering

Using rf cathode sputtering of a target in the oxygen atmosphere, Ba$_{0.6}$Sr$_{0.4}$TiO$_{3}$ solid solution thin films have been formed on the single-crystal Si(001) cut surface and their crystal structure, microstructure, and optical characteristics have been investigated. It is shown that the films are optically anisotropic, polycrystalline, and have a $c$ axis preferred direction perpendicular to the substrate. The $a$ and $b$ axes in the substrate plane have no preferred direction. It has been established that, during the synthesis, a buffer layer with a thickness of about 20 nm forms between the film and substrate, which is optically equivalent to silicon oxide.