X-ray analysis of epitaxial thin film grown on an (001) substrate by metal - organic chemical vapour deposition

Abstract

Using metal - organic chemical vapour deposition (MOCVD) under reduced pressure at , stoichiometric thin films have been epitaxially grown on (001) single-crystal substrates. A series of x-ray analyses have been carried out to study the microstructures and phase transition process in the as-grown films. X-ray diffraction patterns revealed a pure perovskite phase of the thin film. The epitaxial nature of the film was confirmed by a Laue back-reflection photograph and x-ray scan. From the rocking curve measurement made by the synchrotron radiation method at the Beijing Synchrotron Radiation Facility (BSRF), an a-, c-domain coexisting structure in the 4500 Å thin film had been observed with the c-axis of the c-domain perpendicular to the film surface and the a-axis a-domain tilted away from the surface normal. The phase transition process of the thin film was investigated through the high-temperature scan patterns; a higher than in the single crystal had been observed. The strain-driven domain boundary movement in the film was studied by the relative diffraction intensity variation of the (200) and (002) planes.