Enhanced breakdown strength of BaTiO <sub>3</sub> ‐based multilayer ceramic capacitor by structural optimization
Qian Liu, Hua Hao, Qinghu Guo, Zhong‐Hui Shen, Jian Wang, Minghe Cao, Zhonghua Yao, Hanxing Liu
Abstract
Abstract 0.5 wt% Nb 2 O 5 doped 0.12BiAlO 3 ‐0.88BaTiO 3 (12BA5N) multilayer ceramic capacitor (MLCC‐1) was prepared, which satisfied EIA X 7 R specification (where X is the minimum temperature, R is the percentage of capacitance variation limit) at 1 kHZ. The distribution of internal electric field under breakdown voltage was simulated by finite element method (FEM), indicating that the electric field strength increased significantly at the terminal of internal electrode. These areas may become the headstream of breakdown for MLCC‐1 due to the shape mutation. In order to improve the breakdown performance of MLCC‐1, it was optimized by 12BA5N + 2G green sheets (prepared by12BA5N ceramic powder with 2 wt% B‐Al‐Si glass additive), then MLCC‐2 was obtained which satisfied EIA X8R specification. Its BDS rose from 20 to 29.4 kV·mm −1 , and the electric field distribution of dielectric layer was also analyzed by FEM. Besides, it was also found that the grain size and the dielectric constants of “core” and “shell” parts for the 12BA5N + 2G dielectric layer both contributed to the enhanced BDS of MLCC‐2 according to the simulation results from FEM.