Microstructure of epitaxial SrRuO3 films on Si(001) substrates

Abstract The microstructure of pulsed-laser-deposited SrRuO3 films on Si(001) with SrO buffer layers has been studied by means of high-resolution electron microscopy and energy-dispersive X-ray spectroscopy. It was found that good epitaxial growths of the SrO buffer layers and the subsequent SrRuO3 films were achieved on the Si(001) substrates. Multiple domains were formed in the SrRuO3 films with domain boundaries nearly perpendicular to the interface between the SrRuO3 films and the SrO buffer layers. A high density of planar defects, such as twins, stacking faults and antiphase boundaries, were formed along the (022) lattice plane of the SrRuO3 films. Lattice strains in the constituting layers were investigated by means of fast Fourier transformation of local regions in the high-resolution images. It was found that, close to the interface between the SrRuO3 films and the SrO buffer layers, both the layers were elastically strained in the opposite sense. The structure of coherent twin boundary in the SrRuO3 films was determined using a computer-aided high-resolution image simulation method. The comparison between the simulated and the experimental images indicated that the Sr-O plane constituted the twin boundary.