Preparation and Dielectric Properties of SrTiO₃/BaTiO₃ Multilayer Thin Films by Sol-Gel Method

Abstract

SrTiO 3 /BaTiO 3 multilayer thin films were prepared at 650° C on Pt(111)/SiO 2 /Si(100) substrates by the dip-coating method using metal alkoxides. No formation of (Ba, Sr)TiO 3 solid solution between BaTiO 3 layers and SrTiO 3 layers was detected in X-ray diffraction analysis. The SrTiO 3 /BaTiO 3 multilayer thin films consisted of grain structure with grain size of about 30 nm. A film thickness of about 20 nm was obtained by one cycle of the dip-coating/heating process. The SrTiO 3 /BaTiO 3 multilayer thin films with a thickness of 400 nm exhibited dielectric constants of about 400 and loss tangent of 0.03. By reheating the multilayer thin films at temperatures up to 1000° C, (Ba 1- x Sr x )TiO 3 solid solution with the composition gradient between Ba and Sr was formed.