Quantitative Effects of Preferred Orientation and Impurity Phases on Ferroelectric Properties of SrBi2(Ta1-xNbx)2O9 Thin Films Measured by X-Ray Diffraction Reciprocal Space Mapping

Effects of preferred orientation and impurity phases on the ferroelectric property of SrBi2(Ta1-xNbx)2O9 (SBTN) thin films deposited by pulsed metalorganic chemical vapor deposition (pulsed-MOCVD) were quantitatively characterized by employing the X-ray diffraction reciprocal space mapping (XRD-RSM) technique. The SBTN thin films deposited on Pt/Ti- and Pt/TiO2-coated SiO2/(001) Si substrates were found to have {103} preferred orientation and that deposited on Ir/TiO2-coated SiO2/(001) Si substrate was found to have {207} preferred orientation, although conventional θ–2θ profiles of these films showed similar patterns and showed no specific information on preferred orientation. Moreover, the existence of impurity phases such as fluorite and pyrochlore phases were also clearly distinguished from the SBTN phase, and the relative volume fractions of each phase were estimated. The observed remanent polarizations of these films can be explained by taking account of the orientation of the SBTN phase and the volume fraction of the impurity phases. This shows that the XRD-RSM technique is a useful technique for the quantitative estimation of the ferroelectricity of polycrystalline SBTN film.