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arXiv · 2312.13504

Annealing reduces Si$_3$N$_4$ microwave-frequency dielectric loss in superconducting resonators

Sarang Mittal·Kazemi Adachi·Nicholas E. Frattini·Maxwell D. Urmey·Sheng-Xiang Lin·Alec L. Emser·Cyril Metzger·Luca Talamo·Sarah Dickson·David Carlson·Scott B. Papp·Cindy A. Regal·Konrad W. Lehnert
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Abstract

The dielectric loss of silicon nitride (Si$_3$N$_4$) limits the performance of microwave-frequency devices that rely on this material for sensing, signal processing, and quantum communication. Using superconducting resonant circuits, we measure the cryogenic loss tangent of either as-deposited or high-temperature annealed stoichiometric Si$_3$N$_4$ as a function of drive strength and temperature. The internal loss behavior of the electrical resonators is largely consistent with the standard tunneling model of two-level systems (TLS), including damping caused by resonant energy exchange with TLS and by the relaxation of non-resonant TLS. We further supplement the TLS model with a self-heating effect to explain an increase in the loss observed in as-deposited films at large drive powers. Critically, we demonstrate that annealing remedies this anomalous power-induced loss, reduces the relaxation-type damping by more than two orders of magnitude, and reduces the resonant-type damping by a factor of three. Employing infrared absorption spectroscopy, we find that annealing reduces the concentration of hydrogen in the Si$_3$N$_4$, suggesting that hydrogen impurities cause substantial dissipation.

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Sarang Mittal, Kazemi Adachi, Nicholas E. Frattini, Maxwell D. Urmey, Sheng-Xiang Lin, Alec L. Emser, Cyril Metzger, Luca Talamo, Sarah Dickson, David Carlson, Scott B. Papp, Cindy A. Regal, Konrad W. Lehnert. 2023-12-21. Annealing reduces Si$_3$N$_4$ microwave-frequency dielectric loss in superconducting resonators. https://doi.org/10.1103/physrevapplied.21.054044

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