Authors: H.J. Zhao, T.L. Ren, J.S. Liu, L.T. Liu and Z.J. Li
Affilation: Institute of Microelectronics, Tsinghua University, China
Pages: 502 - 505
Keywords: PZT, thick film, lift-off, SU-8
Lead-zirconate-titanate (PZT) is a typical ferroelectrical material with outstanding properties. The demand for the thickness of PZT films used in MEMS is usually over 1_m due to the advantages of the thick thin films, so the integration processes of silicon-based PZT films are the points. In recent years, various methods of fabrication of PZT thick films have been proposed. However, these methods have low compatibility with conventional IC/MEMS processes or can not obtain enough large actuator forces. The present paper proposes a simple fabrication technique of high quality PZT thick films with a single coat and using a thick photoresist SU-8 which call for lift-off technique. The PZT films obtained using single spin-coating with the thickness of 100_m or higher, which is proportional to the thickness of the photoresist SU-8, are crack-free and have good morphology. The PZT films with perfect perovskite structure have excellent piezoelectric property and the d33 is about 170pC/N. Ferroelectric hysteresis loops are measured, and the remnant polarization (Pr) of the PZT ceramics pellet is about 25mC/cm2 and the coercive field (EC) is about 27kV/cm. In the radio-frequency (RF) region, the dielectric constant is about 350 and the dielectric loss is less than 0.01.