Effect of microstructure of MgO buffer layer on BaTiO 3 grown on silicon substrates

Abstract

MgO ultrathin films were grown on Si(1 0 0) substrates as buffer layers for the growth of ferroelectric BaTiO 3 thin films by laser molecular beam epitaxy (L-MBE). The deposition process of MgO buffer layers grown on silicon was in situ monitored by reflection high-energy electron diffraction (RHEED). The structure of BaTiO 3 films fabricated on MgO buffers was investigated by X-ray diffraction. Biaxially textured MgO was obtained at high laser energy density, but when the laser energy was lowered, MgO buffer was transformed to the form of texture with angular dispersion with the increase of the film thickness. BaTiO 3 films grown on the former buffer were completely (0 0 1) textured, while those on the latter were (0 0 1) preferred orientated. Furthermore, the fabricated MgO buffers and BaTiO 3 films had atomically smooth surface and interface. All these can reveal that the quality of textured MgO buffer is a key factor for the growth of BaTiO 3 films on silicon.