Leakage current behavior of SrBi2Ta2O9 ferroelectric thin films on different bottom electrodes

SrBi2Ta2O9 thin films on various bottom electrodes/substrates such as Pt/TiO2/SiO2/Si (Pt) and LaNiO3/Pt/TiO2/SiO2/Si (LNO) were grown using the pulsed laser deposition technique. X-ray diffraction studies revealed that as-grown (at 500 degreesC) films were crystallized in the layered structure after annealing at 800 degreesC. Films grown on platinized silicon exhibited maximum value of remanent polarization (2P(r)similar to21.5 muC/cm(2)) with coercive field (E-c) of similar to67 kV/cm. The dielectric constant and dissipation factor also decreased with the introduction of a 50 nm conducting LaNiO3 oxide electrode at the interface of Pt and SBT thin films, which might be contributed by the high resistive oxide electrode layers. The dc leakage characteristics of the films were studied at elevated temperatures and the data were fitted with the Schottky emission model. The barrier heights of the films grown on Pt and LNO substrates were estimated to be 1.27 and 1.12 eV with optical dielectric constants of 6.3 and 17, respectively. The reduction in barrier height was attributed to the lower work function of the LNO electrode. (C) 2002 American Institute of Physics.