GROWTH OF PEROVSKITE-TYPE THIN-FILMS BY MBE

Epitaxial ultrathin films of BaTiO3 have been prepared using molecular beam epitaxy on SrTiO3 (001) substrate. Since growth condition of the se films was controlled as well as semiconductive film growth, the BaT iO3 films were characterized by X-ray diffraction even in the ultrathi n range. The ultrathin BaTiO3 films were tetragonal phase and highly c -axis oriented single crystal of good film quality. Their tetragonalit y was much larger than the bulk value of BaTiO3, and decreases with in creasing thickness. The epitaxial effect is discussed in terms of a cr itical thickness, as well as a fully strained layer of fine particles.