Nanoscale Chemical and Electrical Characterization of Local Oxygen Vacancies Migration in the Degraded Multilayer Ceramic Capacitors

Nanoscale chemical and electric field distributions of local oxygen vacancies migration in the degraded multilayer ceramic capacitors (MLCCs) are characterized by atomic force microscope‐based infrared technology (AFM‐IR) and Kelvin probe force microscopy. The spatial distribution of local oxygen vacancies is successfully achieved by AFM‐IR based on the electrostatic interaction between the negative‐charged hydroxyl group of H 2 O molecules and the positive‐charged oxygen vacancies due to their electrostatic force. It is found that the concentrations of local oxygen vacancies near the cathode are three times higher than that close to the anode side. Such remarkably different distributions of local oxygen vacancies give rise to local electric field concentration and p–n junction formation in the MLCCs. The present results give us a new perspective to understand local oxygen vacancies distribution and their influence on the local electric reliability of the degraded MLCCs.