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



Pete Hopkins, Manuel Castellanos Beltran, Christine A. Donnelly, Paul Dresselhaus, David Olaya, Adam 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
Sorrento, IT


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


Hopkins, P. , Castellanos Beltran, 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, IT, [online], (Accessed March 2, 2024)
Created June 11, 2017, Updated April 12, 2022