Influences of barrier height and space charge on DC breakdown in BaTiO/sub 3/-based ceramic capacitors

摘要

DC breakdown in BaTiO/sub 3/-based multilayer ceramic capacitors (MLCs) was studied. An abnormal depressed dc breakdown region near the Curie temperature of BaTiO/sub 3/ was observed. It was found that the crystal microstructure of BaTiO/sub 3/-based ceramic in Curie temperature region transformed from the ferroelectric tetragonal phase to the paraelectric cubic phase while the barrier height increases. We assumed the increasing barrier height become a resistance of electrons injecting into the interface at a lower electrical field, and results in a large number of electrons transiently inject into the interface at a higher field, which causes severe transient electronic thermal breakdown and electromechanical breakdown in Curie temperature. That provides high dc breakdown probability in Curie temperature region, which results in an abnormal low dc breakdown field.