Breakdown in lead zirconate titanate (PZT) thin film capacitors

Lifetime of PZT capacitors was defined and evaluated by measuring critical number of cycles where electrical degradation (increase of leakage current) begins to dominate polarization during fatigue tests. It was observed that external failure (electrode burst) occurs during fatigue before electrical degradation at high voltage and/or temperature. The normal internal failure (electrical degradation and breakdown) is predominant at relatively lower voltage and/or temperature. PZT capacitors with smaller electrode size shows shorter lifetime, and gentler input cycles (triangular wave rather than square wave, for example) reduces external failure, which implies breakdown under AC input voltage is related to thermal process. It was noticed that fatigue mechanism is not directly related to thermal breakdown.