Partial discharge characteristics in layered barium titanate structures

Pd characteristics for MLC capacitors with different relative permittivities, porosity, and void size distributions were evaluated. The results show that: 1. Pd is a strong function of and increases with the increase of the applied field. 2. Higher dielectric constant, which gives a bigger field enhancement, also enhances the Pd activity. 3. The source of Pd is the ionization discharge across the voids in the bulk as well as those adjacent to the electrodes. Knowing the void size distribution, the Pd characteristics are generally predictable. 4. The cause of low breakdown for a dielectric with high porosity is that the regions of thin dielectric associated with porosity cannot withstand a high field as the voltage across a void drops significantly by the partial discharge.