Dielectric Properties of Pb(Zr,Ti)O 3 Heterolayered Films Prepared by Sol–Gel Method

Ferroelectric Pb(Zr,Ti)O3 (PZT) heterolayered thin films were fabricated by the alkoxide-based sol–gel method. PZT (20/80) and PZT (80/20) stock solutions were made and alternately spin-coated on the Pt/Ti/SiO2/Si substrate. Each layer was dried at 300°C for 30 min and sintered at 650°C for 1 h. The coating and heating procedure was repeated 6 times to form heterolayered films. PZT film thickness, obtained by one cycle of drying/sintering, was approximately 80 nm. The PZT heterolayered films showed dense and fine grain structures with a grain size of less than 0.2 µm. The relative dielectric constant and the dielectric loss of the 6-coated PZT heterolayered film(PZT-6) were approximately 1385 and 3.3%, respectively. As the number of coatings increased, remanent polarization increased, the coercive field decreased and the values for 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 8.8 ×10-13 A/cm2.