Preparation and characterization of sol-gel derived PZT thin films for micro actuators

Crack-free ferroelectric thin films of lead zirconate titanate (Pb(Zr_x,Ti_1-x)O₃: PZT) with thickness of 3 μm for microactuators were fabricated using Sol-Gel spin-coating onto Pt/Ti/SiO₂/Si substrates. The precursor solution was prepared from lead acetate, zirconium-n-propoxide and titanium tetraisopropoxide. 2-propanol was used as the solvent. The crystalline phases as well as preferred orientation in the PZT films were investigated using X-ray diffraction analysis (XRD). The microstructure and composition of the films were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. The well-crystallized perovskite phase and the preferred orientations in the direction of the (100) plane were obtained using the heat treatment for dry at 120 °C, for pyrolysis at 300 °C and for crystallization at 600 °C. The prepared films showed nanometer grains (30-50 nm) with smooth and uniform surface. The dielectric constants and loss values of these films measured at 1 kHz were approximately 1250 and 0.04, respectively, while the remnant polarization and the coercive field were 45.5 μC/cm² and 58.5 kV/cm. Our results suggest that fabrication of good structural quality PZT films of a few micrometers thick for use in micro actuators is possible.