Ultrahigh Vacuum Packaging and Surface Cleaning for Quantum Devices

Mergenthaler, M.; Paredes, S.; Müller, P.; Müller, C.; Filipp, S.; Sandberg, M.; Hertzberg, J.; Adiga, V. P.; Brink, M.; Fuhrer, A.

doi:10.48550/arxiv.2010.12090

Cited by 1 publication

(1 citation statement)

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“…While the loss tangent of Nb oxide has been studied [22], [23], the contribution of these components to the microwave loss and their evolution during oxide growth is poorly understood. Furthermore, limited strategies for mitigating the losses have been explored [24].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Microwave Loss Induced by Oxide Regrowth in High- Q Niobium Resonators

et al. 2021

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The coherence of state-of-the-art superconducting qubit devices is predominantly limited by two-level-system defects, found primarily at amorphous interface layers. Reducing microwave loss from these interfaces by proper surface treatments is key to push the device performance forward. Here, we study niobium resonators after removing the native oxides with a hydrofluoric acid etch. We investigate the reappearance of microwave losses introduced by surface oxides that grow after exposure to the ambient environment. We find that losses in quantum devices are reduced by an order of magnitude, with internal Qfactors reaching up to 7×10 6 in the single photon regime, when devices are exposed to ambient conditions for 16 min. Furthermore, we observe that Nb2O5 is the only surface oxide that grows significantly within the first 200 hours, following the extended Cabrera-Mott growth model. In this time, microwave losses scale linearly with the Nb2O5 thickness, with an extracted loss tangent tanδNb2O5 = 9.9×10 -3 . Our findings are of particular interest for devices spanning from superconducting qubits, quantum-limited amplifiers, microwave kinetic inductance detectors to single photon detectors.

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Section: Introductionmentioning

confidence: 99%