Quantitative evaluation of the degradation acceleration of insulation at local area in multilayer ceramic capacitors

Abstract

The degradation acceleration based on dielectric thickness was evaluated by analyzing the local insulation degraded area in prototype Ni-BaTiO₃ multilayer ceramic capacitors. Locally thinned dielectric layers, resulting from nickel internal electrode bulges, were associated with shorter lifetimes than the mean time to failure observed in highly accelerated life test. A strong correlation was observed between the minimum thickness of the dielectric layer at the degraded area and the lifetime. The electric field acceleration coefficient was derived from the correlation between the electric field strength, calculated from the dielectric thickness at the degraded area, and the lifetime. The impact of dielectric thinning on degradation acceleration was quantified by analyzing these local degraded areas. The factors influencing degradation acceleration were also discussed based on these findings.