Effect of alloying Ni inner electrodes on the leakage current degradation of BaTiO3-based multilayer ceramic capacitors
High-capacitance multilayer ceramic capacitors (MLCCs) are mostly electronic ceramic components in which Ni inner electrodes and BaTiO3-based dielectrics are laminated alternately. Owing to their usefulness in portable electronic devices such as smartphones, there is an ongoing demand to attain an MLCC with smaller dimensions and improved capacity. We investigated the effect of alloying Ni inner electrodes with various elements on the leakage current degradation of MLCCs. Fe, Cu, Zn, and Sn were chosen and added to Ni and co-fired with BaTiO3, from which Cu and Sn were alloyed with Ni. The leakage current degradation time of MLCCs using the Ni-Cu and Ni-Sn inner electrodes was longer than that of MLCCs using the Ni internal electrodes. In particular, the leakage current degradation of the MLCCs using Ni-Sn inner electrodes was significantly suppressed. This suppression effect increased as the thickness of the BaTiO3-based dielectrics decreased. This method of optimization of the Ni inner-electrode composition could lead to further miniaturization and increased capacity of MLCCs.