Comparison Study of (001)-/(100)-Oriented Epitaxial and Fiber-Textured Pb(Zr,Ti)O3 Thick Films Prepared by MOCVD

Abstract

(001)-/(100)-oriented epitaxial PZT films and fiber-textured PZT films with a thickness of 2 μ m were deposited on (100) c SrRuO3//(100)SrTiO3 and (111)Pt/TiO2/SiO2/(100)Si substrates, respectively, by metalorganic chemical vapor deposition (MOCVD). Crystal structure and the electrical properties were compared for epitaxial PZT films with those of fiber-textured ones, which had the same out-of-plane orientation but different in-plane orientation. The constituent phase change from the single phase of tetragonal PZT, mixture phases of tetragonal and rhombohedral ones and the single phase of rhombohedral one for both films when the Zr/(Zr + Ti) ratio increased. The out-of-plane lattice parameter of (001)- and (100)-axes of PZT films were almost the same value for both films. This indicates the residual strain in the PZT films was almost the same. Dielectric constant (ϵ r) took the maximum value around the MPB composition for (001)-/(100)-oriented fiber-textured films but was almost independent of the Zr/(Zr + Ti) ratio for epitaxial ones. Moreover, there was no significantly dependence of remanent polarization (P r) value on the Zr/(Zr + Ti) ratio for (001)-/(100)-oriented fiber-textured films, while it took minimum value near the morphotropic phase boundary (MPB) for epitaxial ones.