Formation and Microwave Losses of Hydrides in Superconducting Niobium Thin Films Resulting from Fluoride Chemical Processing
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- Department of Materials Science and Engineering Northwestern University Evanston IL 60208 USA
- National Institute of Standards and Technology Boulder CO 80305 USA
- Department of Physics Colorado School of Mines Golden CO 80401 USA
- Rigetti Computing Berkeley CA 94710 USA
- Center for Applied Physics and Superconducting Technologies Northwestern University Evanston IL 60208 USA, Department of Physics and Astronomy Northwestern University Evanston IL 60208 USA, Department of Physics University of Oregon Eugene OR 97403 USA
- Hearne Institute of Theoretical Physics Department of Physics and Astronomy Louisiana State University Baton Rouge LA 70803 USA
- National Institute of Standards and Technology Boulder CO 80305 USA, Department of Physics University of Colorado Boulder CO 80309 USA, Department of Electrical Computer and Energy Engineering University of Colorado Boulder CO 80309 USA
- Department of Materials Science and Engineering Northwestern University Evanston IL 60208 USA, Northwestern University Atomic and Nanoscale Characterization Experimental Center (NUANCE) Northwestern University Evanston IL 60208 USA
- Department of Materials Science and Engineering Northwestern University Evanston IL 60208 USA, Department of Chemistry Northwestern University Evanston IL 60208 USA, Department of Electrical and Computer Engineering Northwestern University Evanston IL 60208 USA
Abstract Superconducting niobium (Nb) thin films have recently attracted significant attention due to their utility for quantum information technologies. In the processing of Nb thin films, fluoride‐based chemical etchants are commonly used to remove surface oxides that are known to affect superconducting quantum devices adversely. However, these same etchants can also introduce hydrogen to form Nb hydrides, potentially negatively impacting microwave loss performance. Here, comprehensive materials characterization of Nb hydrides formed in Nb thin films as a function of fluoride chemical treatments is presented. In particular, secondary‐ion mass spectrometry, X‐ray scattering, and transmission electron microscopy reveal the spatial distribution and phase transformation of Nb hydrides. The rate of hydride formation is determined by the fluoride solution acidity and the etch rate of Nb 2 O 5, which acts as a diffusion barrier for hydrogen into Nb. The resulting Nb hydrides are detrimental to Nb superconducting properties and lead to increased power‐independent microwave loss in coplanar waveguide resonators. However, Nb hydrides do not correlate with two‐level system loss or device aging mechanisms. Overall, this work provides insight into the formation of Nb hydrides and their role in microwave loss, thus guiding ongoing efforts to maximize coherence time in superconducting quantum devices.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 2335952
- Alternate ID(s):
- OSTI ID: 2432454
- Journal Information:
- Advanced Functional Materials, Journal Name: Advanced Functional Materials Journal Issue: 36 Vol. 34; ISSN 1616-301X
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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