Bi-layered PZT films by combining thick and thin film technology

PZT thick films on various substrates are of great interest for applications as pressure sensors, micropumps, ultrasonic and pyroelectric transducers, deformable mirrors and ferroelectric printing forms. Until now, functional properties and microstructure of such films were still not sufficiently solved. Concerning the application as a printing form in an electrostatic printing process a homogeneous microstructure of the PZT film is necessary in order to homogenize the relevant surface potential. Though PZT thin films show very fine grains and thus allow excellent resolution, their surface potential is unstable due to the low internal resistance. Therefore, we have performed an investigation in order to find out whether the combination of thick and thin film technology results in films which can be homogeneously polarized on a scale <20 μm, corresponding to a printing resolution better than 1200 dpi. Results on preparation, characterization and modeling of bi-layered PZT films are presented.