Defect engineering boosts the reliability of ultra-thin MLCCs

Abstract

Modern electronics highly demand base metal electrode multilayer ceramic capacitors (BME MLCCs) with ultra-thin dielectric layers and high capacitances owing to the trend for miniaturization. The reliability of MLCCs is crucial for practical applications and significantly affected by the lamination process and material defects. However, the detailed relationships between these factors and the reliability of ultra-thin MLCCs remain elusive. In this study, we investigated the influence of different lamination pressures (denoted as S1, S2 and S3) on the microstructure and reliability of BaTiO3 (BT) based protocol MLCCs with hundreds of layers. Microstructural observations reveal that among the devices, S2 has the highest roughness for both the Ni internal electrode and dielectric layers. Dielectric property investigations show that S1 and S3 meet the X5R standard and the designed capacity of 10 μF while S2 fails to meet the X5R standard at high temperatures. The electron energy loss spectra investigation reveal that oxygen vacancies are asymmetrically distributed on both sides of the Ni-BT interface in the individual dielectric layers, especially for S2, which indicates that one-side pressure lamination from the bar bulk induces sintering differences on the two sides of the dielectric layer. The results from this study indicate that applying an appropriate critical pressure between BT and Ni (S1) is preferable for decreasing the asymmetry and improving the reliability of MLCCs with ultra-thin layers.