Non-arrhenius behavior in lifetime estimation during highly accelerated lifetime test for multilayer ceramic capacitors

Precise estimation of lifetime for multilayer ceramic capacitors (MLCCs) has become more and more important due to the sharp increase in demand for automotive MLCCs. Since the failure of MLCCs is a thermally activated process, the lifetime estimation is commonly practiced by fitting mean times to failure from highly accelerated lifetime tests using Arrhenius equation. However, we found that the mean time to failure data obtained from 55 degrees C to 85 degrees C for every 5 degrees C is not linear in log-log scale, which is a prerequisite for Arrhenius behavior. Instead, the data points can be best-fit by the Vogel-Fulcher-Tammann equation. The suitability of the Vogel-FulcherTammann equation was rationalized by the fact that the highly accelerated lifetime tests are performed in a paraelectric regime, while the lifetime to be estimated involves a ferroelectric order. We further showed that the underlying mechanism for the failure during highly accelerated lifetime tests is mainly due to a self-heating by unavoidable leakage current, confirmed by a COMSOL Multiphysics simulation. We expect that this newly proposed model is sure to help the community properly estimate the lifetime of MLCCs.