Piezoelectric Pzt Thin Films: Deposition, Evaluation and Their Applications

Piezoelectric thin films have attracted attention as key materials of next generation functional micro-devices. Application products of piezoelectric thin films have been launched such as micropumps for inkjet heads, micro gyrosensors and dual stage actuator (DSA) for hard disk drive (HDD). In addition, piezoelectric vibration energy harvesters (PVEHs) are one of the promising applications of the piezoelectric thin films. In these piezoelectric microelectromechanical systems (MEMS), device performance strongly depends on the function of piezoelectric thin films, especially their transverse piezoelectric properties. Therefore, deposition of high-quality piezoelectric thin films is a crucial technology in piezoelectric MEMS. On the other hand, precise measurement of piezoelectric coefficient of thin films was indispensable for the research and development on piezoelectric thin-films devices. In this paper, we introduce fundamental technologies of piezoelectric thin films and their related micro-devices, especially focusing on sputtering deposition of PZT thin films and evaluation methods of their transverse piezoelectric properties.