Ferroelectric Properties of Very Thin Pb(Zr0.4Ti0.6)O3Film Determined by Kelvin Force Microscope

We attempted to examine scaling issues in terms of PbZr 0.4 Ti 0.6 O 3 (PZT) film thickness. Several very thin PZT films were obtained by the combination of the wet cleaning method and the etch-back process. The polarizability of PZT film was evaluated by measuring the surface potential utilizing the Kelvin force microscope (KFM) mode. The surface potential decreased as the thickness of the PZT film decreased. In particular, the decreasing rate of the surface potential was accelerated below 60 nm, which indicates a possible limitation of the PZT film thickness in terms of the remnant polarization value. Additionally, the retention property as a function of PZT film thickness was also examined by measuring the surface potential in terms of elapsed time. The result shows that the retentivity of the remnant polarization becomes worse as the film thickness decreases.