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arXiv · 2605.30768

Geometric dependence of critical-current variation in Al/AlO${\rm _x}$/Al Josephson junctions: a model-based analysis

K. Kakuyanagi·N. Teran·H. Toida·S. Saito
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Abstract

Achieving uniform critical current across Josephson junctions is essential for the large-scale integration of superconducting quantum circuits. In this work, we statistically analyzed the variation of the critical current of Al/AlO${\rm _x}$/Al junctions using room-temperature tunnel resistance statistics, and identified the dominant contribution among the modeled sources of the variation based on their dependence on geometry and deposition conditions of junctions. Our model-based analysis reveals that fluctuations in the Al film thickness play the dominant role among the modeled contributing factors. Based on this analysis, we found that, in Dolan-bridge double-angle deposition, adopting a deposition angle of 30-degree for bilayer junctions significantly improves uniformity, yielding a relative standard deviation of 1.2% (0.5%) across a 9.75 mm (1.5 mm) square region.

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K. Kakuyanagi, N. Teran, H. Toida, S. Saito. 2026-05-29. Geometric dependence of critical-current variation in Al/AlO${\rm _x}$/Al Josephson junctions: a model-based analysis. https://arxiv.org/abs/2605.30768

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