Growth and characterization of non-c-oriented epitaxial ferroelectric SrBi2Ta2O9 films on buffered Si(100)

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Abstract
We have grown non-c-oriented SrBi2Ta2O9 (SBT) epitaxial thin films with well-defined (116) orientation by pulsed laser deposition on yttria-stabilized zirconia-buffered (YSZ-buffered) Si(100) substrates covered with electrically conductive (110)-oriented SrRuO3 (SRO) bottom electrodes. The epitaxial growth of (110)-oriented SRO films on (100)-oriented YSZ on Si(100) was confirmed both by x-ray pole figures and transmission electron microscopy (TEM) analyses showing a diagonal-type rectangle-on-cube epitaxy of SRO on YSZ with respect to the substrate and yielding specific multiple twins which originate from the particular in-plane positioning of SRO on YSZ. Cross-sectional TEM analyses revealed a roof-like morphology at the SBT/SRO interface while the other interfaces are sharp. The ferroelectric measurements of the (116)-oriented SBT films show a remanent polarization (2Pr) of 6.8 μC/cm2 and a coercive field (2Ec) of 142 kV/cm for a maximum applied electric field of 283 kV/cm. A comparable hysteresis loop recorded from local piezoresponse by an atomic force microscope working in a piezoelectric mode has also been obtained.