Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits
Artikel i vetenskaplig tidskrift, 2024

We demonstrate aluminum-on-silicon planar transmon qubits with time-averaged T1 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.
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npj Quantum Information

20566387 (eISSN)

Vol. 10 Nummer/häfte 1 art. nr 78

Forskningsprojekt

Open Superconducting Quantum Computers (OpenSuperQPlus)

Europeiska kommissionen (EU) (EC/HE/101113946), 2023-03-01 -- 2026-08-31.

Wallenberg Centre for Quantum Technology (WACQT)

Knut och Alice Wallenbergs Stiftelse (KAW 2017.0449, KAW2021.0009, KAW2022.0006), 2018-01-01 -- 2030-03-31.

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Ämneskategorier (SSIF 2011)

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Annan elektroteknik och elektronik

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Identifikatorer

DOI

10.1038/s41534-024-00868-z

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Senast uppdaterat

2025-01-14