Fundamental Study on Nucleation Process of Hydrothermally Synthesized PZT Poly-crystalline Film PZT

Recently, piezoelectric transducer has been used for generation and detection of ultrasound. in medical ultrasound equipment and ultrasound non-destructive inspection equipment. In our laboratory, we fabricated a piezoelectric transducer with PZT poly-crystalline film deposited on the titanium substrate by a hydrothermal synthesis method which is one of crystal growth technology. Fabrication of anti-acoustic cavitation hydrophone [1], cavitation sensor [2] and coiled-stator-type micro ultrasound motor [3] with hydrothermally synthesized PZT piezoelectric transducer have been reported. The hydrothermally synthesized PZT thick film has many favorable features as follows: the hydrothermal process is able to make crystalline films at low temperatures [4]; the films can be deposited on concave or convex Ti substrates with thickness of 10 m [5]; hydrothermally deposited PZT film is hard to be peeled from the boundary of Ti substrate, annealing process is not required [5]. However, deposition rate of hydrothermal poly-crystalline PZT is 2 m / 24 hours in our laboratory. Therefore, there is a problem that it takes long time for deposition of the hydrothermally synthesized PZT poly-crystalline film with required thickness. Furthermore, relationship of the piezoelectric properties and deposition efficiency with respect to the deposition time has not been considered. In this study, we evaluate the influence of the deposition time in the nucleation process of the hydrothermally synthesized PZT poly-crystalline film deposited on the titanium substrate of characteristics