PREPARATION OF HIGH-TC OXIDE SUPERCONDUCTORS AT LOW SUBSTRATE-TEMPERATURE BY FACING-TARGETS SPUTTERING

Y-Ba-Cu-O thin films were prepared at low substrate temperature (T s≤500°C) by a facing-targets-sputtering (FTS) system. MgO〈100〉 and SrTiO3〈110〉 substrates were used in this study. According to the x-ray-diffraction patterns, as-deposited Y-Ba-Cu-O thin films prepared by the FTS system crystallized in the tetragonal phase. The composition of the Y-Ba-Cu-O thin films was almost the same as that of the targets. In the FTS system the growing film on the substrate would not be bombarded by high-energy particles such as γ electrons and negative ions since the substrate is set in a plasma-free position. Consequently, the difference between the film composition and that of the target does not occur due to resputtering. Finally, at a Ts of about 410°C, high-T c oxide superconductors of Y-Ba-Cu-O thin films were obtained by the FTS system. The film surfaces were very smooth. There was no difference between the film composition and that of the target. Tc was about 85 K.