PREPARATION OF YBA2CU3OY THIN-FILMS USING INDUCTION-COIL-COUPLED SPUTTERING

YBa2Cu3Oy (YBCO) superconducting thin films were deposited on MgO sing le crystals by induction-coil-coupled sputtering. The effects of the i nduction coil on the qualities of YBCO thin films are examined. Unifor mity of film thicknesses below +/-5% was obtained over an area of 40 m m diameter using a 50 mm diameter target by the condition of the subst rate-target distance of 90 mm. Even in the area of 60 mm diameter whic h was wider than that of the target, the uniformity of thickness withi n +/-17% was obtained. In order to clarify the effects of the inductio n-coil, we studied the dependence of the critical temperature (T-c) an d the full width at half maximum (FWHM) of the films on the applying p ower of coil. T-c and FWHM showed optimum Values at the applying coil power of 70W. It is confirmed from these results that the induction-co il operated effectively to fabricate high quality films. The epitaxial relations of YBCO films on MgO single crystal substrates were examine d by X-ray pole figure measurements. Basically film of YBCO was aligne d with the c-axis perpendicular to the substrate surface. The film dep osited at the coil power of 70W exhibited well single-oriented grains with the a- or b-axis parallel to the a-axis of MgO. However, films de posited at the applying coil power of 0W contained grains with two dif ferent orientations which were rotated by 45 degrees. Scanning electro n microscopy (SEM) of the film surface showed the films to consist of a smooth background surface and a distribution of particles. Energy di spersive X-ray analysis (EDAX) measurements showed that the Ba concent ration was larger than that of exact stoichiometric composition. Auger electron spectroscopy (AES) revealed that the elements contained in t he particles were richer in Ba than in the smooth background surface. The BaCuO2 particles seemed to precipitate on the surface of the film.