DOUBLE-LAYER EMBEDDED GROUNDING SURFACE TYPE JOSEPHSON DEVICE

摘要

PURPOSE:To prevent erroneous operation due to magnetic flux arresting, by embedding the third superconductor, which has a higher critical superconducting temperature than any of the grounding surface and the first and second superconductors, in the grounding surface, with the area including a circuit function part. CONSTITUTION:A double-junction squid circuit is constituted by Josephson junctions 103 and 104, which are formed between first and second superconductors 101 and 102 comprising a niobium film. A function part is a region 106 including the Josephson junctions 103 and 104 and a bridge between both junctions. A third superconductor 110 has a size than can includes the region 106. The superconductor is embedded in a groove in a grounding surface 107 comprising a superconductor. The surface is flattened. The critical superconducting temperature is higher than that of the superconductors 101, 102 and 107. The width of a control line 105 in the circuit function part 106 is smaller. Therefore, the arresting probability of magnetic flux by the control line 105 is smaller than the arresting probability by the superconductor 110. Thus erroneous circuit operation can be prevented. The more the raw piece of the superconductor 110 is limited to the necessary parts, subdivided in small pieces and arranged on the chip, the more effective the function.