Enhanced superconducting qubit performance through ammonium fluoride etch

The performance of superconducting qubits is often limited by dissipation and two-level systems (TLS) losses. The dominant sources of these losses are believed to originate from amorphous materials and defects at interfaces and surfaces, likely as a result of fabrication processes or ambient exposur...

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Main Authors: Cameron J Kopas, Dominic P Goronzy, Thang Pham, Carlos G Torres Castanedo, Matthew Cheng, Rory Cochrane, Patrick Nast, Ella Lachman, Nikolay Z Zhelev, André Vallières, Akshay A Murthy, Jin-su Oh, Lin Zhou, Matthew J Kramer, Hilal Cansizoglu, Michael J Bedzyk, Vinayak P Dravid, Alexander Romanenko, Anna Grassellino, Josh Y Mutus, Mark C Hersam, Kameshwar Yadavalli
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:Materials for Quantum Technology
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Online Access:https://doi.org/10.1088/2633-4356/ad88cc
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author Cameron J Kopas
Dominic P Goronzy
Thang Pham
Carlos G Torres Castanedo
Matthew Cheng
Rory Cochrane
Patrick Nast
Ella Lachman
Nikolay Z Zhelev
André Vallières
Akshay A Murthy
Jin-su Oh
Lin Zhou
Matthew J Kramer
Hilal Cansizoglu
Michael J Bedzyk
Vinayak P Dravid
Alexander Romanenko
Anna Grassellino
Josh Y Mutus
Mark C Hersam
Kameshwar Yadavalli
author_facet Cameron J Kopas
Dominic P Goronzy
Thang Pham
Carlos G Torres Castanedo
Matthew Cheng
Rory Cochrane
Patrick Nast
Ella Lachman
Nikolay Z Zhelev
André Vallières
Akshay A Murthy
Jin-su Oh
Lin Zhou
Matthew J Kramer
Hilal Cansizoglu
Michael J Bedzyk
Vinayak P Dravid
Alexander Romanenko
Anna Grassellino
Josh Y Mutus
Mark C Hersam
Kameshwar Yadavalli
author_sort Cameron J Kopas
collection DOAJ
description The performance of superconducting qubits is often limited by dissipation and two-level systems (TLS) losses. The dominant sources of these losses are believed to originate from amorphous materials and defects at interfaces and surfaces, likely as a result of fabrication processes or ambient exposure. Here, we explore a novel wet chemical surface treatment at the Josephson junction-substrate and the substrate-air interfaces by replacing a buffered oxide etch (BOE) cleaning process with one that uses hydrofluoric acid followed by aqueous ammonium fluoride. We show that the ammonium fluoride etch process results in a statistically significant improvement in median $\text{T}_1$ by $\sim22\%$ ( p  = 0.002), and a reduction in the number of strongly-coupled TLS in the tunable frequency range. Microwave resonator measurements on samples treated with the ammonium fluoride etch after niobium deposition and etching also show $\sim33\%$ lower TLS-induced loss tangent compared to the BOE treated samples. As the chemical treatment primarily modifies the Josephson junction-substrate interface and substrate-air interface, we perform targeted chemical and structural characterizations to examine materials differences at these interfaces and identify multiple microscopic changes that could contribute to decreased TLS losses.
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spelling doaj-art-e6e88d4a421f4fdc910803785b0e9e5c2025-08-20T02:52:42ZengIOP PublishingMaterials for Quantum Technology2633-43562024-01-014404510110.1088/2633-4356/ad88ccEnhanced superconducting qubit performance through ammonium fluoride etchCameron J Kopas0https://orcid.org/0000-0002-6184-2987Dominic P Goronzy1https://orcid.org/0000-0003-2856-4732Thang Pham2Carlos G Torres Castanedo3https://orcid.org/0000-0002-4505-7970Matthew Cheng4Rory Cochrane5Patrick Nast6Ella Lachman7Nikolay Z Zhelev8https://orcid.org/0000-0002-5344-6298André Vallières9https://orcid.org/0000-0003-0769-8432Akshay A Murthy10https://orcid.org/0000-0001-7677-6866Jin-su Oh11https://orcid.org/0000-0002-7462-3142Lin Zhou12https://orcid.org/0000-0003-2286-6510Matthew J Kramer13https://orcid.org/0000-0002-9097-6730Hilal Cansizoglu14Michael J Bedzyk15https://orcid.org/0000-0002-1026-4558Vinayak P Dravid16Alexander Romanenko17Anna Grassellino18Josh Y Mutus19Mark C Hersam20https://orcid.org/0000-0003-4120-1426Kameshwar Yadavalli21Rigetti Computing , Berkeley, CA, United States of AmericaDepartment of Materials Science and Engineering, Northwestern University , Evanston, IL, United States of AmericaDepartment of Materials Science and Engineering, Northwestern University , Evanston, IL, United States of AmericaDepartment of Materials Science and Engineering, Northwestern University , Evanston, IL, United States of AmericaDepartment of Materials Science and Engineering, Northwestern University , Evanston, IL, United States of AmericaRigetti Computing , Berkeley, CA, United States of AmericaRigetti Computing , Berkeley, CA, United States of AmericaRigetti Computing , Berkeley, CA, United States of AmericaCenter for Applied Physics and Superconducting Technologies, Northwestern University , Evanston, IL, United States of America; Department of Physics and Astronomy, Northwestern University , Evanston, IL, United States of America; Department of Physics, University of Oregon , Eugene, OR, United States of AmericaGraduate Program in Applied Physics, Northwestern University , Evanston, IL 60208, United States of America; Fermi National Accelerator Laboratory , Batavia, IL, United States of AmericaFermi National Accelerator Laboratory , Batavia, IL, United States of AmericaAmes National Laboratory, U.S. Department of Energy , Ames, IA, United States of AmericaAmes National Laboratory, U.S. Department of Energy , Ames, IA, United States of AmericaAmes National Laboratory, U.S. Department of Energy , Ames, IA, United States of AmericaRigetti Computing , Berkeley, CA, United States of AmericaDepartment of Materials Science and Engineering, Northwestern University , Evanston, IL, United States of America; Department of Physics and Astronomy, Northwestern University , Evanston, IL, United States of AmericaDepartment of Materials Science and Engineering, Northwestern University , Evanston, IL, United States of America; Northwestern University Atomic and Nanoscale Characterization Experimental Center (NUANCE), Northwestern University , Evanston, IL, United States of AmericaFermi National Accelerator Laboratory , Batavia, IL, United States of AmericaFermi National Accelerator Laboratory , Batavia, IL, United States of AmericaRigetti Computing , Berkeley, CA, United States of AmericaDepartment of Materials Science and Engineering, Northwestern University , Evanston, IL, United States of America; Department of Chemistry, Northwestern University , Evanston, IL, United States of America; Department of Electrical and Computer Engineering , Northwestern University, Evanston, IL, United States of AmericaRigetti Computing , Berkeley, CA, United States of AmericaThe performance of superconducting qubits is often limited by dissipation and two-level systems (TLS) losses. The dominant sources of these losses are believed to originate from amorphous materials and defects at interfaces and surfaces, likely as a result of fabrication processes or ambient exposure. Here, we explore a novel wet chemical surface treatment at the Josephson junction-substrate and the substrate-air interfaces by replacing a buffered oxide etch (BOE) cleaning process with one that uses hydrofluoric acid followed by aqueous ammonium fluoride. We show that the ammonium fluoride etch process results in a statistically significant improvement in median $\text{T}_1$ by $\sim22\%$ ( p  = 0.002), and a reduction in the number of strongly-coupled TLS in the tunable frequency range. Microwave resonator measurements on samples treated with the ammonium fluoride etch after niobium deposition and etching also show $\sim33\%$ lower TLS-induced loss tangent compared to the BOE treated samples. As the chemical treatment primarily modifies the Josephson junction-substrate interface and substrate-air interface, we perform targeted chemical and structural characterizations to examine materials differences at these interfaces and identify multiple microscopic changes that could contribute to decreased TLS losses.https://doi.org/10.1088/2633-4356/ad88ccsuperconducting qubitstwo-level systemsfabricationinterfaces
spellingShingle Cameron J Kopas
Dominic P Goronzy
Thang Pham
Carlos G Torres Castanedo
Matthew Cheng
Rory Cochrane
Patrick Nast
Ella Lachman
Nikolay Z Zhelev
André Vallières
Akshay A Murthy
Jin-su Oh
Lin Zhou
Matthew J Kramer
Hilal Cansizoglu
Michael J Bedzyk
Vinayak P Dravid
Alexander Romanenko
Anna Grassellino
Josh Y Mutus
Mark C Hersam
Kameshwar Yadavalli
Enhanced superconducting qubit performance through ammonium fluoride etch
Materials for Quantum Technology
superconducting qubits
two-level systems
fabrication
interfaces
title Enhanced superconducting qubit performance through ammonium fluoride etch
title_full Enhanced superconducting qubit performance through ammonium fluoride etch
title_fullStr Enhanced superconducting qubit performance through ammonium fluoride etch
title_full_unstemmed Enhanced superconducting qubit performance through ammonium fluoride etch
title_short Enhanced superconducting qubit performance through ammonium fluoride etch
title_sort enhanced superconducting qubit performance through ammonium fluoride etch
topic superconducting qubits
two-level systems
fabrication
interfaces
url https://doi.org/10.1088/2633-4356/ad88cc
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