Optimizing Josephson Junction Reproducibility in 30 kV E-Beam Lithography: An Analysis of Backscattered Electron Distribution

TL;DR

This paper investigates how to improve the consistency of Josephson junction fabrication using e-beam lithography by analyzing electron distribution effects.

Contribution

The study introduces a novel geometric strategy to control dose uniformity, achieving high reproducibility in Josephson junction fabrication.

Findings

A success rate of up to 96.3% was achieved using a double-resist 1-step low-energy e-beam lithography process.

Simulated stability regions were used to design junction geometries that improve dose uniformity.

Backscattered electron distribution significantly impacts the reproducibility of Josephson junctions.

Abstract

This paper explores methods to enhance the reproducibility of Josephson junctions, which are crucial elements in superconducting quantum technologies, when employing the Dolan technique in 30 kV e-beam processes. The study explores the influence of dose distribution along the bridge area on reproducibility, addressing challenges related to fabrication sensitivity. Experimental methods include e-beam lithography, with electron trajectory simulations shedding light on the behavior of backscattered electrons. Wedescribe the fabrication of various Josephson junction geometries and analyze the correlation between the success rates of different lithography patterns and the simulated distribution of backscattered electrons. Our findings demonstrate a success rate of up to 96.3% for the double-resist 1-step low-energy e-beam lithography process. As a means of implementation strategy, we provide a geometric example that takes advantage of simulated stability regions to administer a controlled, uniform dose across the junction area, introducing novel features to overcome the difficulties associated with fabricating bridge-like structures.

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