Effect of a driving electric field waveform on piezoelectric displacement of PZT thick films

Endurance properties of piezoelectric-induced longitudinal displacement for lead zirconate titanate (PZT) thick films were investigated to develop microelectromechanical systems (MEMS). A 5-µm-thick film was prepared using chemical solution deposition (CSD). Square and triangle waveforms and various frequencies of unipolar or bipolar electric fields were applied to the film. The effects of applied field switching cycles on the ferroelectric properties and longitudinal displacements were measured using a twin-laser interferometer system. Under the bipolar applied field switching condition, the remanent polarization and piezoelectric displacement decreased concomitantly with increasing applied field switching cycles, similar to fatigue behavior. The applied field switching waveform and frequency affect the fatigue profile. The piezoelectric displacement did not decrease when the unipolar square and triangle waveform were applied to the samples. These results suggest that the unipolar driven PZT thick films are applicable to MEMS devices.