Depressed DC Breakdown Phenomena near Curie Temperature of BaTiO3-Based Ceramic Capacitors

Abstract

In this paper, temperature-dependent dc breakdown in BaTiO3-based multilayer ceramic capacitors (MLCs) is studied. We measured dc breakdown fields (BDFs) at temperatures ranging from room temperature to 250°C. According to the change in the breakdown characteristics with temperature, the breakdown process can be regarded as consisting of three regions: room, Curie and 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 important role during dc breakdown in the room and Curie temperature regions. In the high temperature region, the thermal breakdown tends to dominate the breakdown process of MLCs. In addition, based on a structure controlled Schottky conduction process, we combined the thermionic emission process with the influence of barrier height on space charge accumulation. By relating the combined result with the experimental results, it was concluded that the abnormal depression in the dc breakdown is consistent with the change in barrier height caused by the phase transition of the BaTiO3-based ceramic insulator near its Curie temperature.