Effect of interactions at the cofired interface of electrode/ceramics on the reliability of lead-based multilayer ceramic capacitors

The increase of silver content in the internal electrodes was found to have a negative influence on accelerated-test life of lead magnesium niobate-based multilayer ceramic capacitors under direct current-voltage. Transmission electron microscopy (TEM) and auger electron spectroscopy (AES) analyses were carried out on the cofired electrode/ceramics interfaces to demonstrate the effect of Ag content in the electrode on the reliability of capacitors. The result showed that Ag could diffuse into the ceramic layers for more than one micrometer. We designed Ag-doping experiments to study the interactions between the ceramics and Ag. Temperature-humidity-bias (THB) tests on Ag-doped disc specimens revealed that the failure rate of the specimens increased with the Ag content in the ceramics. Based on these results, it was inferred that the deterioration of the multilayer ceramic capacitors with the increase of Ag content in the electrodes should be attributed to the Ag diffusion from the electrodes into the oxide ceramics.