Electrical properties of polycrystalline and epitaxially grown PZT thin films

Polycrystalline and epitaxial PZT films with thickness ranging from 30 nm to 350 nm, which have the same (100)-orientation, were prepared by metalorganic chemical vapor deposition (MOCVD). It was confirmed that the epitaxial films had a larger remanent polarization than polycrystalline films. It was also confirmed that the epitaxial films had a lower thickness dependence of the remanent polarization and that the epitaxial films displayed a good hysteresis curve even when the film thickness was less than 100 nm. These experimental data indicate that the crystal quality of the film strongly affects the ferroelectricity of the film.