Design and fabrication of 10 V SINIS Josephson arrays for programmable voltage standards

Abstract

The fabrication and the chip layout of 69120 SINIS Josephson junction series arrays for a programmable 10 V Josephson dc voltage standard are presented. Under 70 GHz microwave irradiation, the current-voltage characteristic exhibits a non-hysteretic voltage step with a step width of 200 µA. The chip can be operated with the conventional SIS Josephson voltage standard systems.

Single-Chip 10-V Programmable Josephson Voltage Standard System Based on a Refrigerator and Its Precision Evaluation

“…Because the voltage per JJ is at most 100 μV, hundreds of thousands of JJs are required for obtaining a voltage greater than 10 V. For example, the voltage of a JJ is about 33 μV at a microwave frequency of 16 GHz: more than 300 000 JJs are necessary to produce a voltage of 10 V. However, implementation of such a large number of JJs is difficult because of problems related to the fabrication yield. Considerable efforts have been expended for improving the fabrication yield [3]- [7]. Manuscript A solution to the aforementioned problems is to use a systemlevel approach: the use of a multichip technique is very promising for avoiding the aforementioned problem, particularly for the fabrication of superconducting large scale integrated circuits [8].…”

Development of Josephson voltage standards

“…The 1 V arrays contain 8,192 junctions. The first 10 V arrays consisting of 69,120 junctions were also developed shortly afterwards (Schulze et al, 2000) and later significantly improved (Mueller et al, 2007). In spite of their successful use, a serious drawback of SINIS junctions is their sensitivity to particular steps during fabrication often resulting in a few shorted junctions of a SINIS series array (typically between 0 and 10 of 10,000 junctions) probably due to the very thin insulating oxide barriers (cf.…”

Operating Margins of a 10 V Programmable Josephson Voltage Standard Circuit Using ${\rm NbN}/{\rm TiN}_{x}/{\rm NbN}/{\rm TiN}_{x}/{\rm NbN}$ Double-Junction Stacks

“…demonstrated a programmable 1V Josephson voltage standard using Nb/PdAu/Nb junctions with an product of about 30 , corresponding to a characteristic frequency of 15 GHz [3]. Schulze et al. reported the fabrication of junction arrays for a 10V PJVS with a 200 step width, which included 69 120 junctions [5]. Chong et al.…”