Dielectric and Piezoelectric Properties of PZT 52/48 Thick Films with (100) and Random Crystallorgraphic Orientation

Ferroelectric Pb(Zr 1划x Ti x )O 3 (PZT) films have been extensively studied for active components in microelectromechanical systems. The properties of PZT films depend on many parameters, including composition, orientation, film thickness and microstructure. In this study, the effects of crystallographic orientation on the dielectric and transverse piezoelectric properties of Pb(Zr 0.52 Ti 0.48 )O 3 (PZT 52/48) films are reported. Crack free random and highly (100) oriented PZT(52/48) films up to ∼ 7 μm thick were deposited using a sol-gel process on Pt (111)/Ti/SiO 2 /Si and Pt(100)/SiO2/Si substrates, respectively. The dielectric permittivity (at 1kHz) for the (100) oriented films was 980-1000, and for the random films ∼ 930-950. In both cases, tana was less than 0.03. The remanent polarization (∼ 30 μC/cm 2 ) of random PZT films was larger than that of (100) oriented PZT films. The transverse piezoelectric coefficient (d 31(eff) ) of PZT films was measured by the wafer flexure method. The d 31(eff) coefficient of random PZT thick films (-80pC/N) was larger than that of (100) oriented films (-60pC/N) when poled at 80 kV/cm for 15 min.