Programmable Josephson Voltage Standard Circuits Using Arrays of NbN/TiN/NbN/TiN/NbN Double-Junction Stacks Operated at 10 K

摘要

Programmable Josephson voltage standard (PJVS) circuits using arrays of NbN/TiN/NbN/TiN/NbN double-junction stacks were fabricated and operated at a temperature of 10 K. Four arrays each with 32 768 junctions produced expected voltage outputs when driven at (10, 15, 17, and 20) GHz with an operating current range of 0.2-1.0 mA. Another circuit showed constant-voltage steps at ±6 V when driven with an 11 GHz microwave bias, indicating that over 260 000 junctions were operating properly. This circuit did not show constant-voltage steps when driven with a 19 GHz microwave bias, which was the design frequency to achieve ±10 V output voltage.