Synthesis, structure, and optical characteristics of barium–strontium niobate thin films

Films of the Ba 0.5 Sr 0.5 Nb 2 O 6 (BSN) solid solution on the MgO(001) substrate were fabricated by high-frequency RF sputtering in oxygen. Optical spectra of discharge glow when sputtering the BSN ceramic target and the structure and optical characteristics of BSN/MgO(001) films at room temperature were investigated. It was shown that the BSN films grow from a dispersed phase in the discharge gap, while their growth rate with the used deposition mode at the initial stage is 8–9 nm/min. It was established that the grown films are single-crystal, contain twins, and film surfaces are parallel to the crystallographic planes (001). The angle, at which the reflection intensity is independent of the film thickness, was found in the family of specular reflection curves of H -polarized radiation with wavelengths of 500–800 nm from the films under study at room temperature. The tangent of this angle is equal to the refractive index of the film material, while its presence indicates the identity of optical characteristics of the film material of different thicknesses and low roughness of their surfaces.