Role of grain boundaries on hydrogen-induced degradation in lead zirconate titanate thin films

It is well known that exposing lead zirconate titanate (PZT) thin films to hydrogen severely degrades the electrical properties. This phenomenon has been the subject of intensive study; however, there is no electrical evidence relating the hydrogen-induced degradation with the grain boundaries in the films. In this work, using large-grained PZT thin films (average grain size: 40 μm), we could measure the effects of grain boundary on the hydrogen-induced degradation in PZT thin films by locating the upper Pt electrode (8×8 μm2) sequentially from the center of the grain to the grain boundary in a controlled manner. It was found that the grain boundary was mainly responsible for the electrical degradation caused by exposure to the hydrogen. Little degradation with hydrogen exposure was observed when the Pt top electrode was located in the center of the grain.