Thermal activation energy on electrical degradation process in BaTiO3 based multilayer ceramic capacitors for lifetime reliability

For a high capacitance and high lifetime reliability of multilayer ceramic capacitors for automotive applications, the activation energy on thermal activation process can typically be calculated by using Arrhenius based Prokopowicz-Vaskas equation as a method for lifetime prediction. In this study, it is clearly observed that the activation energy shows to be constant in the range of similar to 1.5 eV for the prototype MLCCs, higher than the activation energy values of similar to 1.0 eV related to the motion or diffusion of oxygen vacancies reported in the previous literature. The activation energy value of similar to 1.5 eV for three prototype MLCCs is close to a half the energy band gap (E-g/2 approximate to 1.6 eV) of BaTiO3 obtained from specific environment, where oxygen vacancies are stabilized by external containment such as the effect of rare earth oxide additives. Due to an obvious difference in activation energy values, it difficult to explain the conduction mechanism for failure by only oxygen vacancy migration. Therefore, the concepts of electronic processes and oxygen vacancy should be considered together to understand conduction mechanism for failure of BaTiO3-based MLCCs in thermal activation processes. It can be useful as an indicator for future MLCC development with high lifetime reliability.