Depressed DC breakdown phenomena near Curie temperature of BaTiO3-based ceramic capacitors

In this paper, temperature-dependent dc breakdown in BaTiO3-based multilaye r ceramic capacitors (MLCs) is studied. We measured dc breakdown fields (BD Fs) at temperatures ranging from room temperature to 250 degreesC. Accordin g to the change in the breakdown characteristics with temperature, the brea kdown process can be regarded as consisting of three regions: room, Curie a nd high temperature regions. An abnormal depressed BDF was observed in the Curie temperature region. After analyzing the dc prestressing effect on the dc BDF, it was found that the homo effect of space charges plays an import ant role during dc breakdown in the room and Curie temperature regions. In the high temperature region, the thermal breakdown tends to dominate the br eakdown process of MLCs. In addition, based on a structure controlled Schot tky conduction process, we combined the thermionic emission process with th e influence of barrier height on space charge accumulation, By relating the combined result with the experimental results, it was concluded that the a bnormal depression in the dc breakdown is consistent with the change in bar rier height caused by the phase transition of the BaTiO3-based ceramic insu lator near its Curie temperature.