High DC-Bias Stability and Reliability in BaTiO3-Based Multilayer Ceramic Capacitors: The Role of the Core–Shell Structure and the Electrode

With the miniaturization of multilayer ceramic capacitors (MLCCs) and the increase of the electric field on a single dielectric layer, dielectric constant DC-bias stability and reliability have gradually aroused attention in the advanced electronics industry. In this study, MLCCs with outstanding DC-bias stability and reliability were prepared by using dielectric ceramic optimization and electrode optimization strategies. The effect of the Dy–Y doping concentration on the microstructure, dielectric properties, and reliability of BaTiO3-based ceramics was investigated. The shell ratio and effective shell doping concentration of the core–shell structure in ceramic grains play important roles in defects and electrical performances. The ceramic with appropriate doping contents shows a dielectric constant of 1800 and a dielectric constant change rate of −17% under a DC field of 4 kV/mm, which was fabricated into prototype MLCCs with different Ni electrodes. MLCCs exhibit outstanding DC-bias stability with a −28% degradation in the dielectric constant under a DC field of 4 kV/mm while possessing a dielectric constant of 2300 and satisfying the EIA X7S specification. Additionally, it was discovered that MLCCs prepared by using fine-size Ni particle electrodes have low electrode roughness and high interfacial Schottky barriers, resulting in better reliability. This study provides promising candidate materials and theoretical references for high-end and high DC-bias stability MLCCs.