Structural and dielectric properties of the PZT heterolayered films prepared by sol-gel technique

Ferroelectric PZT heterolayered thin films were fabricated by the alkoxide-based sol-gel method. The PZT(20/80) and PZT(80/20) stock solutions were made and spin-coated on the Pt/Ti/SiO₂/Si substrate by turns. Each layer was dried to remove the organic materials at 300[°C] for 30[min], and sintered at 650[°C] for 1[hr]. This procedure was repeated several times. The thickness of PZT films obtained by one-cycle drying/sintering was about 800[Å]. Relative dielectric constant and resistivity of the PZT films increased with increasing thickness of films, among which the 6-coated PZT heterolayered film (PZT-6) showed the highest values of 1385, 5.8×10⁸[Q-cm], respectively. As the thickness of the films increases, remanent polarization increased and coercive field decreased, and the values of the PZT-6 film were 8.13[μC/cm² ] and 12.5[kV/cm], respectively. The leakage current density of the PZT-6 film at 5[V] was 88.42[pA/cm²]