Tantalum airbridges for scalable superconducting quantum processors

Abstract The unique property of tantalum, particularly its exceptional resistance to both acid and alkali, makes it promising for superconducting quantum processors. Here, we propose a novel lift-off method for fabricating tantalum airbridges with separate or fully-capped structures. This method int...

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Bibliographic Details
Main Authors: Kunliang Bu, Sainan Huai, Zhenxing Zhang, Dengfeng Li, Yuan Li, Jingjing Hu, Xiaopei Yang, Maochun Dai, Tianqi Cai, Yi-Cong Zheng, Shengyu Zhang
Format: Article
Language:English
Published: Nature Portfolio 2025-01-01
Series:npj Quantum Information
Online Access:https://doi.org/10.1038/s41534-025-00972-8
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Summary:Abstract The unique property of tantalum, particularly its exceptional resistance to both acid and alkali, makes it promising for superconducting quantum processors. Here, we propose a novel lift-off method for fabricating tantalum airbridges with separate or fully-capped structures. This method introduces an aluminum film as a barrier layer to separate two layers of photoresist, which is then etched away before depositing tantalum film. We experimentally characterize these tantalum airbridges as control line jumpers, ground plane crossovers and coupling elements, and further validate the overall adaptability by a 13-qubit quantum processor with a median T 1 exceeding 100 μs. The median single-qubit gate fidelity is measured at 99.95(2)% for isolated Randomized Benchmarking and 99.94(2)% for the simultaneous one. Additionally, the experimental achievement of airbridge coupling with a controlled-Z gate fidelity surpassing 99.2(2)% in a separate two-qubit quantum chip may facilitate scalable quantum computation and quantum error correction with entirely tantalum elements.
ISSN:2056-6387