Effect of PbO-coated layer on the microstructure and electrical properties of sol-gel-derived PZT thin films

Highly (100)-oriented lead zirconate titanate Pb(Zr_0.52Ti_0.48)O₃ thin films with and without a PbO-coated layer were prepared on LaNiO₃ (LNO)-coated silicon substrates by a simple sol-gel process. X-ray diffraction and atomic force microscope were applied to study the microstructure of the films. The ferroelectric and fatigue properties were measured by a RT66A system. An infrared spectroscopic ellipsometer was used to determine the thickness of the thin films. The leakage current density (J-T) was carried out with a Keithley 617 programmable electrometer. All measurements were conducted on a Pt-PZT-LNO capacitor structure. It was observed that the PbO-coated layer has no effect on the texture of the PZT thin films while it leads to a great improvement in the surface morphology. The results indicated that samples with a PbO-coated layer show higher remnant polarization and lower coercive field (18.6 (mu) C/cm² and 58.5 kV/cm) than that of samples without PbO-coated layer. After 10⁸ switching cycles, the net-switched polarization for the film with a PbO-coated layer does not show any drop.