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

Area of Science:

• Superconducting quantum technologies
• Advanced materials science
• Nanofabrication

Background:

• Josephson junctions are critical for superconducting quantum computing and electronics.
• The Dolan technique is widely used for fabricating Josephson junctions via e-beam lithography.
• Fabrication sensitivity and reproducibility challenges hinder large-scale quantum technology development.

Purpose of the Study:

• To enhance the reproducibility of Josephson junctions fabricated using the Dolan technique.
• To investigate the impact of dose distribution on fabrication success rates.
• To develop strategies for overcoming fabrication challenges in bridge-like structures.

Main Methods:

• Utilized 30 kV e-beam lithography with a double-resist, 1-step process.
• Performed electron trajectory simulations to analyze backscattered electron behavior.
• Fabricated diverse Josephson junction geometries and correlated success rates with simulated dose distributions.

Main Results:

• Achieved a high success rate of up to 96.3% for the optimized fabrication process.
• Identified a strong correlation between dose distribution and Josephson junction reproducibility.
• Demonstrated that controlling dose uniformity across the bridge area is crucial for success.

Conclusions:

• Optimized e-beam lithography parameters significantly improve Josephson junction reproducibility.
• Simulations of electron scattering are valuable for predicting and controlling fabrication outcomes.
• The proposed geometric implementation strategy offers a pathway to reliable fabrication of superconducting quantum devices.