Coherent superconducting qubits from a subtractive junction fabrication process
| Autor: | Hannes Rotzinger, Jan David Brehm, Alexey V. Ustinov, Valentino Seferai, Sergey Danilin, Alexander Stehli, Tim Wolz, P. G. Baity, Martin Weides |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Shadow mask Quantum Physics Coherence time Fabrication Materials science Physics and Astronomy (miscellaneous) business.industry FOS: Physical sciences 02 engineering and technology Transmon 021001 nanoscience & nanotechnology 01 natural sciences Qubit Condensed Matter::Superconductivity 0103 physical sciences Optoelectronics Time domain 0210 nano-technology business Quantum Physics (quant-ph) Coherence (physics) Electronic circuit |
| ISSN: | 0003-6951 |
| DOI: | 10.48550/arxiv.2006.16862 |
| Popis: | Josephson tunnel junctions are the centerpiece of almost any superconducting electronic circuit, including qubits. Typically, the junctions for qubits are fabricated using shadow evaporation techniques to reduce dielectric loss contributions from the superconducting film interfaces. In recent years, however, sub-micron scale overlap junctions have started to attract attention. Compared to shadow mask techniques, neither an angle dependent deposition nor free-standing bridges or overlaps are needed, which are significant limitations for wafer-scale processing. This comes at the cost of breaking the vacuum during fabrication, but simplifies integration in multi-layered circuits, implementation of vastly different junction sizes, and enables fabrication on a larger scale in an industrially-standardized process. In this work, we demonstrate the feasibility of a subtractive process for fabrication of overlap junctions. In an array of test contacts, we find low aging of the average normal state resistance of only 1.6\% over 6 months. We evaluate the coherence properties of the junctions by employing them in superconducting transmon qubits. In time domain experiments, we find that both, the qubit life- and coherence time of our best device, are on average greater than $20\,\si{\micro\second}$. Finally, we discuss potential improvements to our technique. This work paves the way towards a more standardized process flow with advanced materials and growth processes, and constitutes an important step for large scale fabrication of superconducting quantum circuits. Comment: 8 pages, 7 figures |
| Databáze: | OpenAIRE |
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