Finite element modeling on the effect of intra-granular porosity on the dielectric properties of BaTiO 3 MLCCs

摘要

The effect of porosity on the electrical properties of BaTiO3-based MultilayerCeramic Capacitors (MLCCs) is studied. A dense ceramic prepared via powderfrom a solid-state processing route is compared against a ceramic that containsintra-granular pores from powder prepared via hydrothermal processing. Finiteelement models are created to contain intra-granular pores, solved and analyzed toshow an increase in the electric field and current density surrounding the pores.For single-pore and two intra-pore arrangements, the electric field is enhanced bya factor of~1.5 and 2.5, respectively, when compared to a fully dense (pore-free)material. For ceramics with equivalent density, the number of pores dramaticallyalters the electrical response. For a system containing 100 pores, the electric fieldcan increase at least fourfold, therefore facilitating a possible starting route forelectrical breakdown of the grain. These results are compared to the Gerson-Mar-shall model, typically used in the literature for the calculation of the breakdownstrength due to porosity. The results highlight the need to include the effect ofadjacent pore interactions. Although studied here for BaTiO3-based MLCC’s theresults are applicable to other devices based on ceramics containing porosity.