Metalorganic Chemical Vapor Deposition of Tl sub 2 Ba sub 2 CaCu sub 2 O sub x Superconducting Thin Films Using Fluorinated beta -Diketonate Source Reagents

Superconducting Tl sub 2 Ba sub 2 CaCu sub 2 O sub x films were fabricated using a three-step process. Amorphous BaCaCuOF films were deposted on MgO(100) single-crystal substrates by metalorganic chemical vapor deposition at 500 deg C using fluorinated beta -diketonate complexes of Ba, Ca, and Cu. The fluorine was stripped in wet oxygen at 785 deg C and c-axis oriented Tl sub 2 Ba sub 2 CaCu sub 2 O sub x films were then formed by annealing in dry O sub 2 at 870 deg C in the presence of Tl sub 2 O sub 3 /Ba sub 2 Ca sub 2 CuN sub 3 O sub x pellets. The best films showed onsets of superconductivity at 125K and zero resistivity was achieved by 108K. Critical current densities as high as 10 exp 4 A/cm exp 2 were obtained at 90K. Diffraction patterns, Graphs, Photomicrographs. 11 ref.--AA