Modeling the Electrical Conduction in Epoxy–BaTiO3 Nanocomposites

Abstract

Epoxy–BaTiO3 nanocomposites are widely used as the dielectric material in embedded planar capacitors. To maximize the effective dielectric constant of this nanocomposite, the loading of BaTiO3 is kept as high as possible, but at high loadings of BaTiO3 the magnitude of undesirable leakage current in the dielectric also increases. This paper investigates the conduction mechanism in epoxy–BaTiO3 nanocomposites. Further, the effects of BaTiO3 loading and the size of BaTiO3 particles on the electrical conduction are investigated and also modeled. To investigate the conduction mechanism, capacitor structures (Cu/dielectric/Cu) with nanocomposite dielectric were fabricated using the colloidal process. The loading and size of BaTiO3 particles were varied in the nanocomposite dielectric. Once the capacitor structures were fabricated, the leakage current was measured across the capacitor dielectric as a function of temperature and voltage. The leakage current data were checked for any consistency with the standard conduction models using regression analysis, and the dominant conduction mechanism was identified. Finally, the activation energy of the dominant conduction mechanism was trended as a function of BaTiO3 loading and particle size both experimentally and theoretically.