Key factors determining high-temperature operating lifetime of multilayer ceramic capacitors (MLCCs)

Abstract Improving the high-temperature operating lifetime of multilayer ceramic capacitors (MLCCs) is a critical challenge. Although optimizing dielectric compositions and structures is effective, the relative impacts and generalizability of individual factors remain unclear. In this study, the determining factors for the lifetime of 36 commercial high-volumetric-efficiency MLCCs (EIA Class-II) were statistically evaluated using linear regression models. The results revealed that dielectric layer thickness variation and electrode coverage, which are expected to cause electric field concentration, had negligible effects. In contrast, two variables—rare-earth element concentration and mean grain boundary count (dielectric layer thickness divided by grain diameter)—were identified as generalizable dominant factors. Furthermore, the size of grains in contact with internal electrodes tended to show a stronger influence on the lifetime, suggesting the effectiveness of selectively enhancing the reliability of dielectrics near the electrodes.