Fabrication of Nb-doped Lead Zirconate Titanate Film and Its Electromechanical Properties in Microelectromechanical System Application

Nb-doped lead zirconate titanate (Nb_0.02-Pb(Zr_0.6Ti_0.4)O₃, PNZT) films were prepared on the LaNiO₃/Si substrates by a sol-gel method and a PNZT film driving microcantilever was fabricated by microelectromechanical system (MEMS) technology. The microstructure and electrical properties of PNZT films and electromechanical properties of the microcantilever were investigated. The results show that the silicon-based PNZT film is a perovskite structure with a random crystalline orientation, and its remnant polarization and coercive electric field are 20 μC/cm² and 27 kV/cm, respectively. According to the results obtained by piezoresponse force microscopy (PFM) and microcantilever vibration test, the longitudinal piezoelectric coefficient, d₃₃, and transverse piezoelectric coefficient, d₃₁, are calculated to be 70 pm/V and 90 pm/V, which are as high as those of the reported epitaxial PZT films. In atmospheric environment, the mechanical quality factor, Q, of the microcantilever is calculated to be 122 at first resonant frequency, showing a rather low mechanical dissipation of the microcantilever in the mechanical vibration. It is indicated that the PNZT film could have potential applications in high-performance ferroelectric and piezoelectric MEMS devices.