Orientation dependent ferroelectric properties of SrBi/sub 2/Ta/sub 2/O/sub 9/ ferroelectric thin films

SrBi/sub 2/Ta/sub 2/O/sub 9/ (SBT) thin films With various orientations: [001] oriented, partially [115]&[001] oriented, partially [115]&[200] oriented, and [116] oriented films were grown by rf magnetron sputtering deposition method. The orientations of the films were controlled varying the substrate orientation and the deposition temperature. Their structural properties were investigated by the X-ray diffraction /spl theta/-2/spl theta/ scan. Surface morphologies were examined by atomic force microscope. Longer grains were observed in partially oriented and [116] oriented films than those in [001] oriented film. The remanent polarizations were about 3-5 and 10 /spl mu/C/cm/sup 2/ in partially oriented films and [116] oriented films, respectively. The activation fields were calculated by measuring the switching currents of the samples. The remanent polarizations and the activation fields of various films were explained in conjunction with the inclination of SBT grains to the film surface.