Investigation on the morphology and dielectric properties of PI/BaTiO3 composite films

Polyimides (PI) are widely used in microelectronic industries because of their outstanding characteristics such as good mechanical, thermal and dielectric properties. In this paper, a series of polyimide/barium titanate (PI/BaTiO₃) composite films with different BT volumn contents were prepared. Modifier 3-amino-propyl-triethoxysilane was added during composite preparation to disperse the BaTiO₃ particles in polyimide matrix. The effects of BaTiO₃ addition on the microstructure and properties, especially the dielectric property of composite films were investigated. It was found that thermal stability of the composites could be improved with the incorporation of BaTiO₃ particles. The dielectric constant (ε) and the dielectric loss (tan δ) of these composites increased with the increase of the volume fraction of BT particles, which was 45 and 0.013 respectively at 50 Hz as the composite contains 40vol% BaTiO₃. The results of this work demonstrate the potential use of BaTiO₃ powder for obtaining enhanced dielectric properties in a PI/BaTiO₃ composite for application in an embedded capacitor.