Preparation of ferroelectric bi-layered thin films using the modified polymeric precursor method

The modified polymeric precursor method was used to synthesize ferroelectric bismuth-layered compounds such as, SrBi2Ta2O9 (SBT) and SrBi2Nb2O9 (SBN). This method allows for the use of precursor reagents such as oxide, carbonate or nitrate as cation sources, with the additional advantage of not requiring special equipment for the synthesis. The films were deposited by spin coating on Pt/Ti/SiO2/Si(100) and SrTiO3(100) (STO) substrates and crystallized at temperatures between 700 and 800 °C in the case of SBT films and 650 °C to 750 °C in that of SBN films. The crystallographic and microstructural characterizations were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The ferroelectric and dielectric properties of the films indicate their applicability in ferroelectric memories and optical devices.