RSFQ circuitry realized in a SINIS technology process

We have developed integrated circuits in Rapid Single Flux Quantum (RSFQ) impulse logic based on intrinsically shunted tunnel junctions as the active circuit elements, The circuits have been fabricated using superconductor-insulator-normalconductor-insulator-superconductor (SINIS) multilayer technology. The paper presents experimental results of the operation of various RSFQ circuits realized in different designs and layouts. The circuits comprise dc/SFQ and SFQ/dc converters, Josephson transmission lines (JTL's), T-flipflops, and analog key components. Functionality has been proved; the circuits have been found to operate correctly in switching. The circuits investigated have a critical current density of j(C) = 400 A/cm(2) and a characteristic voltage of V-C = 165 mu V, the area of the smallest junction is A = 24 mu m(2), The junctions exhibit nearly hysteresis-free current-voltage characteristics (hysteresis: less than 7%), the intra-wafer parameter spread for j(C) is below +/- 8%. The margins of the bias current I-b of the circuits have been experimentally determined and found to be larger than +/- 24%, At preset, constant values of I-b, the range of a separate bias current I-b-sw. fed to a switching stage integrated between two segments of JTL's is fully covered by the operation margins which are larger than +/- 56%.