JOSEPHSON JUNCTION

PURPOSE:To enable a Josephson junction to be lessened in noises and enhanced in reproducibility and stability of characteristics by a method wherein the crystal grain boundaries of a YBCO (Y oxide superconductor) thin film formed on the Junction interface of an Si bi-crystal substrate are rejoined. CONSTITUTION:The substrate planes of Si single crystals 1 and 2 are (001) planes, and a [100] axis and a [010] axis are rotated by an angle of 24 deg. on the planes concerned. A second layer 3 of stabilized ZrO2 and a third layer 4 of Y2O3 are formed on this bi-crystal substrate through an electron beam evaporation method. A YBCO thin film is formed on the substrate concerned through an rf sputtering method. The same as above, YSZ and Y2O3 are provided onto an Si bi-crystal substrate where a [100] axis and a [010] axis are rotated by an angle of 9 deg. to form a YBCO thin film. The YBCO thin film is formed into a bridge through a laser etching method for the formation of a Josephson junction.