Highly stable aluminum air-bridges with stiffeners

TL;DR

This paper introduces an optimized geometry for aluminum air-bridges that significantly enhances their mechanical stability, enabling reliable operation in superconducting quantum circuits and addressing a key technological challenge.

Contribution

The study presents a novel air-bridge design that improves stability, validated through systematic testing up to 170 micrometers in length.

Findings

Achieved complete stability for bridges up to 170 micrometers long.

Provided a practical solution for air-bridge instability issues.

Enhanced mechanical robustness for quantum circuit applications.

Abstract

Air-bridges play a critical role in the performance of microwave circuits integrated with superconducting quantum bits, and their mechanical stability is predominant for reliable operation. This study is devoted to the technological issues that lead to air-bridge instability. We propose an optimized bridge geometry designed to enhance mechanical resilience. Through systematic testing, we established that bridges incorporating this novel geometry achieved complete stability for lengths up to 170 micrometers in our technological processes. The findings provide an insight into the problem and a practical solution for technologists that faced with the challenges of air-bridge stability. The implementation of our technology has the potential to significantly improve the mechanical robustness of air-bridges in multi-qubit circuits for quantum computation.