Piezoelectric properties of PZT films prepared by the sol-gel method and their application in MEMS

Pb(Zr_0.52Ti_0.48)O₃ (PZT) piezoelectric thin films with thickness of 0.7-2.2 μm were prepared on Pt/Ti-coated SiO₂/Si (0.5 μm/300 μm) substrates by the sol-gel method. The piezoelectric coefficient e₃₁ of the PZT thin film was − 12.5 ± 0.3 C/m², which is evaluated by measuring the tip displacement of PZT-coated cantilevers of the dimensions 50 mm long, 4 mm wide, and 0.3 mm thick. The prepared PZT films demonstrated excellent piezoelectric properties and have large potential applications in MEMS devices. Micro-machined ultrasonic sensors, in which PZT-coated membrane functioned as sensing element, were fabricated and their properties were also characterized.