Electrical and mechanical properties of PZT thin films prepared by hybrid process of Sol-gel technique and laser ablation

To prepare lead zirconate titanate (Pb(Zr_xTi_1-x)O₃): PZT) thin films at a higher deposition rate and a lower substrate temperature, the PZT films were fabricated by a hybrid process of sol-gel technique and pulsed laser ablation deposition. First, one layer of PZT (about 0.12-0.14 μm) was coated on Si/SiO₂/Ti/Pt substrate by sol-gel process. Then PZT film was deposited at a rate of 0.7 μm/hr by pulsed excimer laser-ablation on the substrate with one sol-gel derived PZT seed layer. A target of Pb(Zr_0.52Ti_0.48)O₃ with 20 wt% excess PbO was used. The substrate temperature was about 500 °C. The film fabricated by the hybrid process showed the perovskite PZT phase without pyrochlore phase. The dielectric constant measured at 1 kHz was approximately 1580. The saturation polarization, remnant polarization and coercive field of 0.8 μm thick film were about 46.6 μC/cm², 24.5 μC/cm² and 36.4 kV/cm, respectively. The residual stresses in the thin film stacks were measured by the changes in the radius of curvature of the wafer. A relatively lower tensile stress (approximately 33 MPa) was obtained compared to the sol-gel derived PZT film. Therefore, the PZT films with good electrical and mechanical properties can be fabricated by using the hybrid process of the sol-gel technique and laser ablation.