P‐N Junction‐Driven Abnormal Electric Field Distribution in the Degraded Multilayer Ceramic Capacitors

• Published in: Physica status solidi. A, Applications and materials science Applications and materials science, 2024-03, Vol.221 (5), p.n/a
• Main Authors: Du, Wentong, Yang, Weiwei, Yi, Cheng, Zhao, Kunyu, Zhang, Faqiang, Liu, Zhifu, Zeng, Huarong
• Format: Article
• Language: English
• Subjects: Barium titanates; Capacitors; Cathode region; Degradation; electric field distributions; Electric fields; Energy bands; Failure mechanisms; Highly accelerated lifetime testing; Insulation; insulation resistance degradation; Kelvin probe force microscopy; multilayer ceramic capacitors; Multilayers; P‐N junction
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.202300871

Local electric field distribution in the dielectric layer of BaTiO3‐based multilayer ceramic capacitors (MLCCs) is investigated by Kelvin probe force microscopy before and after highly accelerated life test (HALT) degradation combined with the energy band diagram. An unusual electric field concentration phenomenon is directly visualized near the HALT cathode region in the degraded MLCCs while a reverse voltage is applied. Such abnormal behavior is ascribed to the migration of oxygen vacancies within the dielectric layer during the HALT, leading to the formation of a P‐N junction structure and further a heightened barrier under a reverse bias. As a result, a P‐N junctional model is proposed for understanding local failure mechanism of the degraded MLCCs, which enrich the insights into the insulation resistance degradation and the reliability of MLCCs. An unusual electric field concentration near the highly accelerated life test cathode in the degraded multilayer ceramic capacitors (MLCCs) with a reverse voltage is visualized by Kelvin probe force microscopy. A P‐N junction model is proposed for understanding the correlation mechanism between the oxygen vacancy migration and the electrical failure of the MLCCs.