Preparation of BaO-Bi₂O₃-TiO₂ System Films by MOCVD and Their Microstructure and Dielectric Properties

Abstract

BaO-Bi₂O₃-TiO₂ system films were prepared on (100)Pt/(100)MgO substrates by metalorganic chemical vapor deposition (MOCVD). The composition of the films was changed in the range of (1-y)BaTiO₃-yBi₄Ti₃O₁₂ (y=0 to 1.0). The effect of composition on the microstructure, morphology and dielectric properties of the films were investigated. BaTiO₃, BaBi₄Ti₄O₁₅, BaBi₈Ti₇O₂₇ and Bi₄Ti₃O₁₂ phases were obtained in the composition between y=0 and 1.0. At y<0.03, Bi-doped BaTiO₃ single phase films were obtained, and the grain size of the films increased with increasing y. The dielectric constant of the Bi-doped BaTiO₃ films showed the maximum value of 1000 at y =0.01, which is 2 times greater than that at y =0. The high dielectric constant might be resulted from the increase of grain size of BaTiO₃.