Side-wall spacer passivated sub-μm Josephson junction fabrication process

    Research output: Contribution to journalArticleScientificpeer-review

    2 Citations (Scopus)

    Abstract

    We present a structure and a fabrication method for superconducting tunnel junctions down to the dimensions of 200 nm using i-line UV lithography. The key element is a sidewall-passivating spacer structure (SWAPS) which is shaped for smooth crossline contacting and low parasitic capacitance. The SWAPS structure enables formation of junctions with dimensions at or below the lithography-limited linewidth. An additional benefit is avoiding the excessive use of amorphous dielectric materials which is favorable in sub-Kelvin microwave applications often plagued by nonlinear and lossy dielectrics. We apply the structure to niobium trilayer junctions, and provide characterization results yielding evidence on wafer-scale scalability, and critical current density tuning in the range of 0.1-3.0 kA cm-2. We discuss the applicability of the junction process in the context of different applications, such as SQUID magnetometers and Josephson parametric amplifiers.

    Original languageEnglish
    Article number125016
    Number of pages6
    JournalSuperconductor Science and Technology
    Volume30
    Issue number12
    DOIs
    Publication statusPublished - 16 Nov 2017
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Josephson junctions
    spacers
    Lithography
    Niobium
    Parametric amplifiers
    Fabrication
    fabrication
    Tunnel junctions
    SQUIDs
    Magnetometers
    lithography
    Linewidth
    Scalability
    Capacitance
    Tuning
    Microwaves
    parametric amplifiers
    tunnel junctions
    niobium
    magnetometers

    Keywords

    • Josephson junction
    • Josephson parametric amplifier
    • magnetometer
    • spacer
    • trilayer
    • tunnel junction

    Cite this

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    title = "Side-wall spacer passivated sub-μm Josephson junction fabrication process",
    abstract = "We present a structure and a fabrication method for superconducting tunnel junctions down to the dimensions of 200 nm using i-line UV lithography. The key element is a sidewall-passivating spacer structure (SWAPS) which is shaped for smooth crossline contacting and low parasitic capacitance. The SWAPS structure enables formation of junctions with dimensions at or below the lithography-limited linewidth. An additional benefit is avoiding the excessive use of amorphous dielectric materials which is favorable in sub-Kelvin microwave applications often plagued by nonlinear and lossy dielectrics. We apply the structure to niobium trilayer junctions, and provide characterization results yielding evidence on wafer-scale scalability, and critical current density tuning in the range of 0.1-3.0 kA cm-2. We discuss the applicability of the junction process in the context of different applications, such as SQUID magnetometers and Josephson parametric amplifiers.",
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    author = "Leif Gr{\"o}nberg and Mikko Kiviranta and Visa Vesterinen and Janne Lehtinen and Slawomir Simbierowicz and Juho Luomahaara and Mika Prunnila and Juha Hassel",
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    language = "English",
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    Side-wall spacer passivated sub-μm Josephson junction fabrication process. / Grönberg, Leif; Kiviranta, Mikko; Vesterinen, Visa; Lehtinen, Janne; Simbierowicz, Slawomir; Luomahaara, Juho; Prunnila, Mika; Hassel, Juha.

    In: Superconductor Science and Technology, Vol. 30, No. 12, 125016, 16.11.2017.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

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    AU - Grönberg, Leif

    AU - Kiviranta, Mikko

    AU - Vesterinen, Visa

    AU - Lehtinen, Janne

    AU - Simbierowicz, Slawomir

    AU - Luomahaara, Juho

    AU - Prunnila, Mika

    AU - Hassel, Juha

    PY - 2017/11/16

    Y1 - 2017/11/16

    N2 - We present a structure and a fabrication method for superconducting tunnel junctions down to the dimensions of 200 nm using i-line UV lithography. The key element is a sidewall-passivating spacer structure (SWAPS) which is shaped for smooth crossline contacting and low parasitic capacitance. The SWAPS structure enables formation of junctions with dimensions at or below the lithography-limited linewidth. An additional benefit is avoiding the excessive use of amorphous dielectric materials which is favorable in sub-Kelvin microwave applications often plagued by nonlinear and lossy dielectrics. We apply the structure to niobium trilayer junctions, and provide characterization results yielding evidence on wafer-scale scalability, and critical current density tuning in the range of 0.1-3.0 kA cm-2. We discuss the applicability of the junction process in the context of different applications, such as SQUID magnetometers and Josephson parametric amplifiers.

    AB - We present a structure and a fabrication method for superconducting tunnel junctions down to the dimensions of 200 nm using i-line UV lithography. The key element is a sidewall-passivating spacer structure (SWAPS) which is shaped for smooth crossline contacting and low parasitic capacitance. The SWAPS structure enables formation of junctions with dimensions at or below the lithography-limited linewidth. An additional benefit is avoiding the excessive use of amorphous dielectric materials which is favorable in sub-Kelvin microwave applications often plagued by nonlinear and lossy dielectrics. We apply the structure to niobium trilayer junctions, and provide characterization results yielding evidence on wafer-scale scalability, and critical current density tuning in the range of 0.1-3.0 kA cm-2. We discuss the applicability of the junction process in the context of different applications, such as SQUID magnetometers and Josephson parametric amplifiers.

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    KW - Josephson parametric amplifier

    KW - magnetometer

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    KW - tunnel junction

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