Abstract
High Tc superconductor films were sputter-grown in several crystalline forms, e.g. the polycrystal, polycrystal with c-axis preferential orientation, and (110) epitaxial crystal. The film had the critical temperature as high as 87 K. The micro-fabrication technique on the basis of the wet etching by the phosphoric acid and FELLIOX-115 was proposed. The thin line (2-4 μm wide) thus made exhibited no significant degradation in its superconductivity. The grain-boundary in the patterned polycrystalline film served as a good Josephson junction operative even at 81 K. The constricted Josephson junction array device was fabricated for the use as a sensitive image sensor. A possible application of this kind of material to the luminescence device is also demonstrated.
