Ferroelectric Properties of Sol-Gel Derived Pb(Zr, Ti)O3 Thin Films

Pb(Zr, Ti)O3 thin films of thickness ranging from 55 nm to 625 nm were synthesized on Pt/Ti/SiO2/Si substrates using a sol-gel process. The film thickness dependence of both microstructure and electrical properties was investigated. The synthesized films showed columnar structure. The diameter of each column was around 100 nm regardless of the film thickness. The 328 nm-thick film exhibited a dielectric constant (ε) of 1000, remanent polarization (P r) of 20 µC/cm2, and coercive field (E c) of 47 kV/cm. Both ε and P r decreased and E c increased with decreasing film thickness. This behavior is attributed to the existence of a low-dielectric-constant interface layer. The results of leakage current measurement were in good agreement with the model of space-charge-limited current.