Preparation of Ba_1-xSr_xTiO₃ Dielectric Film by Electrophoretic Deposition Method with Fine Particle and Investigation on Dielectric Property

Abstract

Recently, Ba_1−xSr_xTiO₃, with a perovskite structure, has drawn much attention as a dielectric material. For this study, we prepared Ba_0.7Sr_0.3TiO₃ films using electrophoretic deposition with Ba_0.7Sr_0.3TiO₃ fine particles of various sizes. For the film-forming process, we optimized the deposition voltage, deposition time, sample concentration, I₂ concentration, and other parameters. Results show that the film thickness is controllable by changing the deposition time and voltage, although higher voltage made the film inhomogeneous. A film prepared with larger particles seemed to have lower density, but the density was improved using heat treatment at higher temperatures. Investigation of dielectric properties of the films revealed that a Ba_0.7Sr_0.3TiO₃ film deposited in 0.5 g·L⁻¹ I₂-added acetone for 8 s at 50 V with a particle size of 0.3 μm and then heat-treated at 900 °C for 30 min had 2.52 μm thickness. It exhibited capacitance density of 113.9 nF·cm⁻².