ABSTRACT
This chapter describes the deposition process of Pb(Zr,Ti)O3 (PZT) thin films from the viewpoint of Microelectromechanical systems (MEMS) applications. In addition, the recent progress of the lead-free piezoelectric thin films is introduced. Among a variety of piezoelectric Microelectromechanical systems (MEMS), the piezoelectric MEMS energy harvesters, and the basic characteristics and applications of piezoelectric MEMS energy harvesters are presented. Deformation of a piezoelectric material generates an electric dipole in a unit cell of the crystal, and summation of individual dipoles becomes polarization, which is converted to the electric output. Piezoelectricity has two characteristics: One is the piezoelectric effect, which means the charge generation by external stress or strain, and the other is the inverse piezoelectric effect, which is force generation by an external electric field. Since the piezoelectric films are deposited on substrates, the piezoelectric effect of the thin film is strongly suppressed by the existence of the substrate, and it makes it difficult to measure the precise piezoelectric properties.
