Improving Josephson junction reproducibility for superconducting quantum circuits: junction area fluctuation

The dominant source of junction resistance non-uniformity is junction area variation²². The deviation of the mask feature size could be minimized by optimizing e-beam lithography (EBL) process^30,31. There is typically a large junction wiring area (1–25 μm²) leading to significant backscattering exposure of Dolan bridge during EBL. We simulated proximity effect using Monte Carlo method for the two different mask stacks: MMA-PMMA A4 and MMA-CSAR 62. The simulations indicate that the dose on the junction area increases by ~ 30% due to backscattering exposure, that corresponds to…