Effect of Y-doping on resistance degradation of multilayer ceramic capacitors with Ni electrodes under the highly accelerated life test

The effect of Y-doping on the degradation behavior of insulation resistance for multilayer ceramic capacitors with Ni electrodes has been studied using electrical measurement techniques such as admittance spectroscopy, thermally stimulated current (TSC), and electrical conductivity measurements. TSC measurements show that a strong internal bias field remained after applying an electrical field at a high temperature, like during highly accelerated life testing. This internal bias field originated from the migration of positive carriers. Admittance spectroscopy indicated three types of relaxation, with activation energies of 0.4, 0.8, and 0.8-1.0 eV. The intensity of the 0.4eV relaxation peak increased with Y3+ doping and disappeared at low oxygen partial pressure (P-O2) annealing. The existence of holes was also observed from the temperature dependence of insulation resistance. The 0.4eV relaxation is considered to be due to the transition of electrons from the valence band to barium vacancy states. These results suggest that Y3+ acts as a donor and creates barium vacancies, which compensate for the oxygen vacancies and thereby improve the resistance to degradation.