PHOTOABSORPTION AND PHOTOCHEMICAL DECOMPOSITION OF COPPER AND ALKALINE-EARTH BETA-DIKETONATES AS SOURCE GASES OF HIGH-TC SUPERCONDUCTING FILMS

For low-temperature deposition of oxide films relating to Bi-Sr-Ca-Cu-O superconductors, photo-absorption and -decomposition properties were examined with respect to copper and alkaline-earth beta-diketonates. It was confirmed that all beta-diketonates examined were promising as source materials for photochemical vapour deposition (photo-CVD) using a low-pressure mercury lamp, in view of their large light absorption coefficients at wavelength 254 nm. The light irradiation was effective for the formation of highly crystalline oxide films at temperatures below 600-degrees-C. By combining two sources, Ca2CuO3 and SrCuO2 films were prepared. Photo-CVD of c-axis oriented Bi2Sr2CuOx film was achieved by the irradiation of ternary sources of Bi(C6H5)3 and strontium and copper beta-diketonates at 500-degrees-C.