Ferroelectric and piezoelectric properties of disk shape lead zirconate titanate thick films

A combination of the preparation techniques for the ferroelectric films and the micro machining of Si is considered to be an effective way to fabricate microelectromechanical systems (MEMS), such as piezoelectric micro-transducer devices for the electrical and medical fields. In this study, disk shape lead zirconate titanate (PZT) thick films were successfully fabricated. 10-mum-thick PZT films were deposited onto Pt/Ti/ SiO2/Si substrate using a chemical solution deposition (CSD) process. Pt top electrode and PZT layer were etched by reactive ion etching (RIE) process, and 100 to 500-mum-diameter PZT thick film disks were fabricated. The relative dielectric constant, dissipation factor, remnant polarization and coercive field were epsilon(r) = 1130, tan delta = 0.02, Pr = 0.14 C/m(2) and Ec = 2.5 MV/m, respectively. This means that the ferroelectric and dielectric properties of the PZT thick film disks were comparable with that of the bulk PZT ceramics. Moreover, the prepared PZT thick film disks showed the butterfly-shaped displacement curve, related with piezoelectric response, in the case of bipolar measurement. The PZT thick film disks could be poled with 80 V at room temperature, which is easier than the poling condition of bulk PZT. The piezoelectric constant of the poled PZT thick film disks was estimated to be AFM d(33) = 221 pm/V. Therefore, the micro fabricated 10-mum-thick PZT disks is considered to be applicable for piezoelectric micro devices.