SUBSTRATE EFFECTS ON THE GROWTH OF EPITAXIAL BATIO3 THIN-FILMS

Epitaxial BaTiO3 thin films were successfully grown on SrTiO3 (001) su bstrate by molecular beam epitaxy. The BaTiO3 films within the thin th ickness range (less than 200 Angstrom) were highly distorted because o f the epitaxial effect. The epitaxial effect depends on not only the s ubstrate material but also the surface roughness of the substrate. In order to investigate the epitaxial effect in a rough surface and in a flat surface, we performed in-situ observation of reflection high-ener gy electron diffraction (RHEED) and ez-situ measurement of X-ray diffr action. The SrTiO3 substrates with different surface roughness were al so succeessfully grown through same growth condition, observed by RHEE D. The X-ray diffraction measurements confirmed that the epitaxial eff ect was enhanced in the BaTiO3 film on the flat surface, but the latti ce parameters were nearly equal to the bulk value.