PURPOSE: To prevent the interlinkage of magnetic fluxes form the outside so that the interference device can make stable operations without generation any magnetic flux trap by forming a ground plane of a superconducting layer so that the ground plane can lie upon the part containing a Josephson element. ;CONSTITUTION: After forming a ground plane 7 and washer cover 8 of a superconducting film, the plane 7 and cover 8 are insulated by means of an interlayer insulating film 11. Then, after depositing the resistor films of the shunt resistor 2 and damping resistor 3 of a direct-current SQUID (direct-current superconducting quantum interference device), the resistor films are insulated by means of the film 11 and the resistances of the resistance films are set to the designed values. Thereafter, in order to manufacture a Josephson junction element 1 composed of a lower electrode 12, barrier layer 13, and upper electrode 14, the electrodes 12 and 14 and layer 13 are deposited and the electrode 14 and layer 13 are etched through a photolithographic process. Therefore, the superconducting layer forming the ground plane 7 lies upon the element 1 over a wide planar area and is electrically insulated from the element 1. therefore, magnetic traps hardly occur and the operations of the SQUID is stabilized.;COPYRIGHT: (C)1994,JPO&Japio
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