Insulation resistance degradation mechanisms of multilayer ceramic capacitors during highly accelerated temperature and humidity stress tests

The failure mechanisms of multilayer ceramic capacitors (MLCCs) with Ni internal electrodes under high temperature and high voltage conditions have been investigated through highly accelerated life tests (HALTs) in recent years. Generally, insulation resistance degradation during HALTs is presumed to be because of the electromigration of oxygen vacancies. Reliability in high-temperature, high-humidity, and rated-voltage environments is important for MLCCs. However, only a few studies have investigated the causes of insulation resistance degradation in MLCCs in these environments. We investigated the failure mechanisms of MLCCs through a highly accelerated temperature and humidity stress test. On the basis of presence of a degraded area on the anode side, we presumed that hydrogen ions were produced by H2O electrolysis at the interface between the ceramics and internal electrodes on the anode side, and that these hydrogen ions caused insulation resistance degradation. (C) 2018 The Japan Society of Applied Physics