Ferroelectric properties of highly (111)-oriented Pb(Zr1-x, Tix)O3 thin films with different Zr/Ti ratios

Pb(Zr1-x, Ti-x)O-3 thin films with different Zr/Ti ratios (0.45 <= x <= 0.49) were prepared by a sol-gel method using nitrate zirconium as starting material and 2-methoxyethanol as solvent. The films were deposited on Pt (111)/Ti/SiO2/Si (100) substrates by spin-coating process and annealed at 650 degrees C for 3 min by rapid thermal annealing (RTA). X-ray diffraction (XRD) revealed that the films crystallized in perovskite phase and were all (111)-oriented. The effect of Zr/Ti ratios on the phase components and ferroelectric properties of the thin films was investigated. The result suggests that monoclinic phase and tetragonal phase coexists for the films with 0.47 <= x <= 0.49 and there is a pure monoclinic phase for the films with x <= 0.46. The films with x <= 0.46 exhibit higher remnant polarizations (2P(rmax) = 44.9 mu C/cm(2)) compared with the other films, as is explained by more monoclinic phase content and higher (111) orientation degree. (C) 2009 Elsevier B.V. All rights reserved.