Fabrication of stabilized piezoelectric thick film for silicon-based MEMS device

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2007-09, Vol.88 (4), p.627-632
• Main Authors: KWON, T. Y, KIM, Y. B, EOM, K, YOON, D. S, LEE, H. L, KIM, T. S
• Format: Article
• Language: English
• Subjects: Applied physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Densification; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electrical properties; Exact sciences and technology; Materials science; Micromachining; Microstructure; Permittivity (dielectric function); Physics; Piezoelectricity; Piezoelectricity and electromechanical effects; Silicon substrates; Thick films
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-007-4025-6

Electrical properties of piezoelectric thick films with controlled microstructure were investigated. In order to enhance the electromechanical properties (e.g. d31, d33) of a thick film by control of its microstructure, a mixed powder, referred to as BNP, consisting of both nano-sized and micro-sized piezoelectric particles, was employed as a starting precursor in the film fabrication process. According to a scanning electron microscopy study, it is shown that a BNP thick film exhibits the densest homogeneous microstructures. According to surface area measurements, the BNP thick film was sufficiently densified without an additional infiltration process of Pb(Zr1-xTix)O3 sol for densification. The screen-printed BNP thick film possesses a dielectric constant and a remanent polarization much higher than those of a thick film composed of only micro-sized piezoelectric particles by a factor of more than two. This suggests the potential application of the BNP thick film, in conjunction with a silicon substrate, to a micromachined monolithic PZT thick film device on the silicon substrate.