Fabrication of Lead Zirconate Titanate Thick Film Disks for Micro Transducer Devices
- PDF / 403,520 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 58 Downloads / 269 Views
D4.5.1
Fabrication of Lead Zirconate Titanate Thick Film Disks for Micro Transducer Devices
Takashi Iijima, Sachiko Ito and Hirofumi Matsuda Smart Structure Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba 305-8568, Japan
ABSTRACT 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, 10-µm-thick disk shape lead zirconate titanate (PZT) thick films were successfully fabricated 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-µm-diameter PZT micro disks were fabricated on Pt/SiO2/Si substrate. The relative dielectric constant, dissipation factor, remnant polarization and coercive field were εr = 1130, tanδ = 0.02, Pr = 14 µC/cm2 and Ec = 25 kV/cm, respectively. This means that the ferroelectric and dielectric properties of the PZT micro disks were comparable with that of the bulk PZT ceramics. The PZT micro disk showed the butterfly-shaped displacement curve, related with piezoelectric response, in the case of bipolar measurement. The piezoelectric constant of the PZT disks poled at 80Vfor 10 min was estimated to be AFM d33 = 221 pm/V. A resonance frequency of the radial oscillation was evaluated to apply for micro transducer devices.
INTRODUCTION Lead zirconate titanate (PZT) films are in demand for applications in many fields like memories, sensors and actuators. Combining the preparation technique for ferroelectric films with a Si micro-machining process is an effective way to fabricate microelectromechanical systems (MEMS), such as piezoelectric micro-actuator devices for electrical and medical fields [1, 2]. However, the amount of the displacement and force of PZT films is not sufficient in some applications, so that various processes were investigated to fabricate thick PZT films, with thickness varied from 5 to 100 µm [3-8]. On the other hand, a low process temperature for the PZT thick films is required to ensure compatibility with the Si micro-machining process. To keep compatibility with the Si micro-machining process for MEMS devices,therefore, a chemical solution deposition (CSD) process is considered to have the advantage of a low firing temperature and dense microstructure despite the low film deposition rate. We investigate preparation process of PZT thick films using the CSD process and successfully prepare more than 10-µm-thick PZT films with dense microstructure [9]. In this study, 10-µm-thick PZT films were deposited onto Pt/Ti/SiO2/Si substrate using CSD process, and Pt top electrode and PZT layer were etched by reactive ion etching (RIE) process to fabricate 100 to 500-µm-diameter PZT
D4.5.2
micro disks. A ferroelectric polarization-field (P-E) hysteresis curve and a longitudin
Data Loading...
