| Autor: |
Janka Biznárová, Amr Osman, Emil Rehnman, Lert Chayanun, Christian Križan, Per Malmberg, Marcus Rommel, Christopher Warren, Per Delsing, August Yurgens, Jonas Bylander, Anita Fadavi Roudsari |
| Jazyk: |
angličtina |
| Rok vydání: |
2024 |
| Předmět: |
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| Zdroj: |
npj Quantum Information, Vol 10, Iss 1, Pp 1-8 (2024) |
| Druh dokumentu: |
article |
| ISSN: |
2056-6387 |
| DOI: |
10.1038/s41534-024-00868-z |
| Popis: |
Abstract We demonstrate aluminum-on-silicon planar transmon qubits with time-averaged T 1 energy relaxation times of up to 270 μs, corresponding to Q = 5 million, and a highest observed value of 501 μs. Through materials analysis techniques and numerical simulations we investigate the dominant source of energy loss, and devise and demonstrate a strategy toward its mitigation. Growing aluminum films thicker than 300 nm reduces the presence of oxide, a known host of defects, near the substrate-metal interface, as confirmed by time-of-flight secondary ion mass spectrometry. A loss analysis of coplanar waveguide resonators shows that this results in a reduction of dielectric loss due to two-level system defects. The correlation between the enhanced performance of our devices and the film thickness is due to the aluminum growth in columnar structures of parallel grain boundaries: transmission electron microscopy shows larger grains in the thicker film, and consequently fewer grain boundaries containing oxide near the substrate-metal interface. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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