A study on the temperature dependence of epoxy/BaTiO3 composite embedded capacitor films

Abstract

In this study, the temperature dependence of capacitance, one of the most important properties of embedded capacitor films (ECFs), was investigated. The temperature dependence of the capacitance of ECFs was determined by the temperature dependence of the dielectric constant and thickness, and among these, the main factor was the dielectric constant of ECFs. The dielectric constant of ECFs was determined by that of epoxy and BaTiO3 powders. Below 130 degrees C, the dielectric constant of ECFs increased as temperature increased, and was mainly affected by an epoxy matrix. However, above 130 degrees C (the Curie temperature of BaTiO3), the increased rate of the dielectric constant of ECFs started decreasing. This was due to the fact that BaTiO3 powder undergoes a phase transition from a tetragonal to a cubic structure, and its dielectric constant decreases at 130 degrees C. The dielectric constant of BaTiO3 powder was obtained from measured dielectric constants of ECF and application of the Lichtenecker logarithmic rule.