A low-loss composition region identified from a thin-film composition spread of (Ba1−x−ySrxCay)TiO3

Abstract

We have generated the thin-film ternary composition spread of $({\mathrm{Ba}}_{\text{1−x−y}}{\mathrm{Sr}}_x{\mathrm{Ca}}_y){\mathrm{TiO}}_{\mathrm{3}}$ on an equilateral-triangle-shaped ${\mathrm{LaAlO}}_{\mathrm{3}}$ substrate. Compositional variation within the triangle was achieved by a precisely controlled shutter system inside a pulsed laser deposition chamber, which allows the deposition of precursors with gradient thickness over the length of the substrate. Appropriate postannealing afforded high-quality epitaxial thin films over almost the entire composition region. Mapping of the microwave dielectric properties of the composition-spread chip was performed using a scanning evanescent microwave microscope at 1 GHz. Composition region ${\mathrm{Ba}}_{\mathrm{0.12–0.25}}{\mathrm{Sr}}_{\mathrm{0.35–0.47}}{\mathrm{Ca}}_{\mathrm{0.32–0.53}}{\mathrm{TiO}}_{\mathrm{3}}$ was found to have desirable properties for electronic applications.