Estimation of hydrothermally deposited lead zirconate titanate (PZT) thin-film

The mechanical output of piezoelectric vibrators, particularly actuators, is determined by the limit of the vibration velocity. To obtain large vibration velocity, it is important to deposit a thick piezoelectric film. We have succeeded in depositing thick lead zirconate titanate (PZT) films by the hydrothermal method. The thicknesses of the films were 2 μm, 9.8 μm, 20 μm and 30 μm when the reaction times were 2, 5, 10, and 15, respectively. We have also estimated Young's modulus of the PZT films from the resonance frequency of the bimorph vibrators. From the measurement results, Young's modulus of the PZT film was 1.3 × 10¹⁰ N/m². This value corresponded to only 16% of that of bulk PZT. The piezoelectric constants of hydrothermally deposited PZT film were inferior to those of bulk PZT. To obtain much larger constants, it is necessary to obtain larger Young's modulus.