BaTiO₃-SrTiO₃積層薄膜の誘電特性

抄録

We aimed at development of thin film capacitor alternatives to multi-layer ceramic capacitor fabricated by sintering. It is necessary to improvement of dielectric properties of BaTiO₃ film up to bulk level. In this study, an artificial dielectric super lattices technique by pulsed laser deposition was performed. Multilayer BaTiO₃-SrTiO₃ thin films were prepared on Pt(111)/Ti/SiO₂/Si(100) or SrTiO₃(111) by controlling the arrangement of perovskite structure A-site ion in nano-scale. The lattice of the films in the hetero-epitaxial interface at (111) plane was expanded by compressive strain due to lattice mismatch. Cycle of layer was evaluated from diffraction angle of satellite peak by equation for superlattice structure. Dielectric constant of the multilayer BaTiO₃-SrTiO₃ thin films enlarged at [BaTiO₃(2.5nm)/SrTiO₃(2.5nm)]₂₀ was 550, compared to solid solution thin film of 390.