Fabrication of surface barrier layer capacitor on BaTiO3-based composite containing particulate SiC

Abstract

Surface reoxidized-type barrier layer (BL) capacitors were prepared by hot-pressing BaTiO3/SiC powder mixture in argon atmosphere and subsequently oxidizing the semiconducting BaTiO3-based composites with fine SiC particles. Dielectric properties, such as apparent relative dielectric constant, dielectric loss tangent, and Curie temperature, were investigated as a function of SiC content and oxidation procedures. Incorporating SiC particles into BaTiO3 matrix, a thin surface insulating layer was formed, which becomes thinner by increasing the SiC content. BL capacitors showing a higher capacitance than 3 × 102 nF/cm2 could be successfully fabricated. The results were discussed on the basis of high resolution transmission electron microscope (HRTEM) studies. Thin oxidized layer and the resulting high capacitance were associated with the depression of oxygen diffusion due to the presence of intergranular SiC particles. The thickness of the surface layer and some dielectric properties could be controlled by the SiC content as well as oxidation temperature and time.