Dresden 2026 – scientific programme
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QI: Fachverband Quanteninformation
QI 11: Implementations IV
QI 11.9: Talk
Wednesday, March 11, 2026, 12:15–12:30, BEY/0245
Toward Chemically Resilient Superconducting Qubit Fabrication — •Niklas Bruckmoser1,2, Leon M. Koch1,2,3, Thomas Brenninger2, Ivan Tsitsilin1,2,3, Amanda Scoles1,2, David Bunch1,2, Julius Feigl1,2, Lea Richard1,2, Christian Gnandt1,2, Christian M.F. Schneider1,2, Vera P. Bader1,2, Haiyang Hu1,2, Lasse Södergren1,2, and Stefan Filipp1,2 — 1Technical University of Munich, TUM School of Natural Sciences, Physics Department, Garching, Germany — 2Walther-Meißner-Institut, BAdW, Germany — 3Peak Quantum GmbH, Germany
As superconducting quantum processors scale up, there is an increasing need for fabrication methods that combine low loss with high yield. One promising strategy is the implementation of subtractive processes that also withstand aggressive interface cleaning, particularly by replacing aluminum with chemically resilient materials. In this talk, we demonstrate a fully subtractive process for niobium-based air bridges that are used as interconnects as well as vacuum-gap capacitors. Rigorous surface cleaning allows us to achieve mean internal quality factors of coplanar waveguide resonators exceeding Qint = 7.9× 106 in the single-photon limit, with no detectable added loss from air bridges. By integrating large vacuum-gap capacitors into transmon qubits, we observe median lifetimes above T1 = 50 µs.
Building on this platform, we share our first exploratory efforts toward the implementation of chemically resilient Josephson junctions. At this early stage, we focus on challenges and discuss pathways to achieve a scalable, high-yield, and low-loss fabrication process.
Keywords: Superconducting Qubits; Fabrication; Quality factor; Air bridge; Transmon