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Scalable, High-Speed, Digital Single-Flux-Quantum Circuits at NIST



Peter F. Hopkins, Manuel C. Castellanos Beltran, Christine A. Donnelly, Paul D. Dresselhaus, David I. Olaya, Adam J. Sirois, Samuel P. Benz


We describe NIST’s capabilities for designing and fabricating niobium-based single-flux quantum (SFQ) digital and mixed-signal circuits and show test results of our first circuits. We have assembled a package of software design tools that are readily available and sufficient for designing, simulating, and optimizing circuits. A scalable process including four niobium metal layers and partial planarization of the insulating layers has been developed based on intrinsically shunted Josephson junctions with tunable niobium-doped amorphous-silicon barriers. This process can be extended to demonstrate dense, high-speed SFQ circuits. Through our participation in IARPA’s Cryogenic Computing Complexity (C3) program, we have built liquid- helium cryogenic probes and test systems with 40 and 80 input/outputs for characterizing advanced SFQ circuits at speeds up to 26 GHz.
Proceedings Title
International Superconductive Electronics Conference
Conference Dates
June 12-16, 2017
Conference Location


Rapid single flux quantum (RSFQ), single flux quantum, Josephson devices, Josephson junctions, Josephson logic, superconducting device fabrication, superconducting integrated circuits


Hopkins, P. , Castellanos, M. , Donnelly, C. , Dresselhaus, P. , Olaya, D. , Sirois, A. and Benz, S. (2017), Scalable, High-Speed, Digital Single-Flux-Quantum Circuits at NIST, International Superconductive Electronics Conference, Sorrento, -1, [online], (Accessed December 4, 2021)
Created June 12, 2017, Updated July 25, 2019