Effect of La doping on the suppression of insulation resistance degradation in multi-layer ceramic capacitors

Abstract

Effect of La doping on the suppression of insulation resistance degradation in multi-layer ceramic capacitors (MLCCs) was investigated. The insulation resistance of La-doped (Ba, Sr)(Ti, Zr)O3 (La-doped BSTZ) MLCCs increased during the early phase of the highly accelerated life test (HALT). The insulation resistance of La-doped BSTZ-MLCCs immediately before breakdown was still higher than that at the early phase. This behavior during the early phase of HALT was eminent for La doping. However, the activation energy of the La-doped BSTZ-MLCCs was the same as those of other rare earth element-doped BaTiO3 MLCCs, suggesting that La-doped BSTZ-MLCCs were also degraded by the migration of oxygen vacancies. Thermally stimulated depolarization current analysis revealed that La-doped BSTZ-MLCCs exhibited trapping of the oxygen vacancies around the grain boundary, which suggested that trapping led to suppression of migration of the oxygen vacancies, and decreased polarization current. This trapping resulted in an increased insulation resistance.