Enhanced reliability of ultra-thin multilayer ceramic capacitors (MLCCs) based on re-oxidation process

Ultra-thin base metal electrodes-multilayered ceramic capacitors (BME-MLCCs) with high volume capacitance are considered to be a charming device for a diverse range of electric applications. Here, we fabricated the MLCCs with ultra-thin layer of ~ 1.2 μm and a high capacitance of ~ 47 μF via high oxygen re-oxidation process. Defect chemistry analysis of the re-oxidation process reveals that about 1 nm thick for inter-diffusion layer between Ni and BaTiO3 appeared in higher oxygen re-oxidation process compared with lower oxygen re-oxidation process dominated by 3 nm thick for inter-diffusion layer. The results show that oxygen vacancy concentration is decreased when oxygen partial pressures of re-oxidation rise from 10–6 to 10–4 atm. In addition, the Schottky barrier at the BaTiO3(BT)–Ni interface increased from 1.30 to 1.82 eV, and the amount of oxygen (x) in BaTiOx at the interface decreased from 3 to 2.75, with a smaller decrease, which is conducive to the improvement of the overall reliability of MLCCs. The final results show that the MLCCs with high oxygen re-oxidation process demonstrated a high breakdown voltage of 52.74 V/μm and superior reliability at 2.5 V and 105 °C. This work demonstrates a strategy of effectively improving the reliability of BME-MLCCs with high capacitances.