2.6-V high-resolution programmable Josephson voltage standard circuits using double-stacked MoSi2-barrier junctions

Using a new circuit design and double-stacked junction technology we have demonstrated fully functional high-resolution programmable voltage standard chips with 67 410 junctions that operate up to a maximum output voltage of 2.6 V. The circuit uses double-stacked junctions, where two junctions are fabricated in each stack, in order to increase the output voltage. We have also improved the voltage resolution at fixed frequencies 16-fold by using a circuit optimized for three voltage states and 128-fold below 2 V by oppositely biasing two large arrays whose junction counts differ by a single stack. These circuits operate over a frequency range from 14 GHz to 19 GHz with a 2-mA maximum operating current range.