GROWTH AND CHARACTERIZATION OF CEO2 FILMS ON SAPPHIRE SUBSTRATES BY SPUTTERING PROCESS

Two-inch-diameter CeO2 films on R-plane (1102) sapphire substrates hav e been prepared using an on-axis rf magnetron sputtering method. The e ffects of postannealing treatment, sputtering gas pressure and substra te temperature on the orientation, crystallinity and surface morpholog y of the CeO2 films have been investigated. The (100)-preferred CeO2 f ilms with high crystallinity are grown at 820 degrees C and 0.15 Torr and have a full width at half-maximum value of the rocking curve of (2 00) planes of 0.15 degrees. The spatial variation of thickness of the CeO2 films across the 2-inch substrate is about 5.8%. The c-axis orien ted YBa2Cu3Ox, (YBCO) films grown on sapphire substrates with a (100)- preferred CeO2 buffer layer of 100 nm are made. The YBCO films have su perconducting properties with the T-c being 88-90 K and J(c) (77K, OT) being (1-3) x 10(6) A/cm(2).