GROWTH AND X-RAY DIFFRACTION OF BaTiO₃ THIN FILMS. Y. Yoneda, T. Okabe, K. Sakaue and H. Terauchi, Dept. of Physics, Kwansei-Gakuin University, Nishinomiya, HYOGO 662, Japan

Thin films of BaTiO₃ single crystal on SrTiO₃ (001) substrate were prepared epitaxy by molecular beam epitaxy (MBE). BaTiO₃ films deposited around 700 deg.C and the deposition rate of these films was 30-70 sec/1 unit. The growth under the condition of the low deposition rate clarifies the growth mechanism of BaTiO₃ films. Our MBE method is different from laser ablation or sputtering. In these methods, radical ion beam is used to enhanced oxidation. However, in our case, molecular beam is neutral electric state.

The BaTiO₃ films, ranging from 5 ML-thick to 20 ML-thick, were investigated by in-situ monitoring of reflection high energy electron diffraction and ex-situ observation of X-ray diffraction. Most films were grown by alternate activated reactive evaporation (ARE). Since the BaTiO₃ film were island growth in co-evaporation, the intensity oscillation in the specularly reflected electron beam was observed only the beginning of growth. However, in alternate ARE, the intensity oscillation was observed throughout the growth. The epitaxial relationship was cube-on-cube. The rocking curve of BaTiO₃ (002) reflection from the 40-Å (10-ML)-thick film indicated that the BaTiO₃ thin films were strong c-axis oriented tetragonal phase.