Aging- and annealing-induced variations in Nb/Al–AlOx/Nb tunnel junction properties

Pavolotsky, Alexey; Dochev, D; Belitsky, Victor

doi:10.1063/1.3532040

Cited by 23 publications

(18 citation statements)

References 28 publications

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“…Three out of the four fitting parameters (RL, RN, and Vg) used in the empirical model are physical parameters, which are extracted from the measured I-V characteristics [22]. The current onset sharpness width coefficient, a, is estimated through fitting and has a typical value of approximately 3-4•10 4 (V -1 ) for the Nb-AlOx-Nb junctions produced in-house [23]. This parameter can be used as a measure of the junction quality, as explained in section II-E.…”

Section: A Quasi-particle Tunnel Currentmentioning

confidence: 99%

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Frequency Multiplier Based on Distributed Superconducting Tunnel Junctions: Theory, Design, and Characterization

Rashid

Krause

Meledin

et al. 2016

IEEE Trans. THz Sci. Technol.

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In this paper, we present the analysis, design and characterization of the first frequency multiplier using distributed SIS junctions. We derived analytical expressions describing the properties of the distributed SIS junction as a frequency multiplier. The modeling of the distributed SIS junctions shows that high conversion efficiency can be achieved when used as the multiplier. The measured output power generated by such multiplier employing the distributed SIS junction at the second harmonic of the input frequency is in good agreement with the model. Furthermore, the frequency multiplier based on distributed SIS junction was for the first time able to pump an SIS mixer. The multiplication efficiency of the distributed SIS junction is 15-30 % for a fractional bandwidth of 10% with excellent spectral line purity. The-3 dB line width of the multiplied signal is 1 Hz, which was limited by the resolution bandwidth of the spectrum analyzer. The results attained in this work show that the distributed SIS junction frequency multiplier has considerable future potential, and could possibly be used in LO source in single-end and multipixel SIS mixer receivers.

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Section: A Quasi-particle Tunnel Currentmentioning

confidence: 99%

“…Fabrication of the DSM chips generally followed the process flow described in [23]. The Nb/Al-AlOx/Nb trilayer was grown in a single vacuum run by means of dc magnetron sputtering.…”

Section: Frequency Multiplier Circuit Design and Fabricationmentioning

confidence: 99%

Frequency Multiplier Based on Distributed Superconducting Tunnel Junctions: Theory, Design, and Characterization

Rashid

Krause

Meledin

et al. 2016

IEEE Trans. THz Sci. Technol.

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“…8 However, an undesirable property of AlO x is “aging” as manifest in drifting electrical properties over time. 9–12 …”

Section: Introductionmentioning

confidence: 99%

Reduced resistance drift in tunnel junctions using confined tunnel barriers

Barcikowski

Pomeroy

2017

Journal of Applied Physics

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Metal-insulator-metal (MIM) tunnel junctions with the aluminum oxide tunnel barriers confined between cobalt electrodes exhibit less resistance drift over time than junctions that utilize a thick, unconfined aluminum electrode. The improved long time stability is attributed to better initial oxide quality achieved through confinement (use of a potential energy well for the oxygen) and plasma oxidation. In this work, Co/AlOx/Co and Co/Al/AlOx/Co tunnel junction aging is compared over a period of approximately 9 months using transport measurements and Wentzel-Kramers-Brillouin (WKB) based modelling. The Co/AlOx/Co (confined) tunnel junction resistance increased by (32 ± 6) % over 5400 h, while Co/Al/AlOx/Co (unconfined) tunnel junction resistance increased by (85 ± 23) % over 5200 h. Fit parameters for the tunnel barrier width and potential energy barriers were extracted using WKB transport modelling. These values change only a small amount in the confined Co/AlOx/Co tunnel junction but show a significant drift in the unconfined Co/AlOx/Co tunnel junction.

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“…The Nb/Al-AlOx/Nb SIS junctions were fabricated in-house following the procedure described in [14]. The SIS junction at the end of a 50 Ω superconducting microstripline is fabricated on a high resistivity Si substrate.…”

Section: Fabrication and DC Characterizationmentioning

confidence: 99%

Direct Measurement of Superconducting Tunnel Junction Capacitance

Aghdam

Rashid

Pavolotsky

et al. 2015

IEEE Trans. THz Sci. Technol.

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Superconductor-Insulator-Superconductor (SIS) is the key component for millimeter and submillimeter mixers for radio astronomy and environmental science. The capacitance of the SIS mixer determines both the RF and IF performances. Previously, the measurements of this capacitance have been followed with high uncertainty levels. Herein, we present the characterization of the SIS junction capacitance at cryogenic temperature (~4 K) by direct measurement of the SIS junction impedance at microwave frequencies allowing accurate characterization of the SIS junction capacitance. The proposed calibration method uses only one short-circuit reference. The SIS junction capacitance measurement is realized by biasing the junction at the different parts of its current-voltage characteristic, thus eliminating a separate measurement of shortcircuit standard. In order to verify the acquired measurement results, thin-film capacitors with known capacitance were also characterized. The capacitances of four SIS junctions with various areas were measured. The absolute uncertainty of the proposed measurement method was found to vary from 5 to 6.8 % amongst different junction areas.

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Aging- and annealing-induced variations in Nb/Al–AlOx/Nb tunnel junction properties

Cited by 23 publications

References 28 publications

Frequency Multiplier Based on Distributed Superconducting Tunnel Junctions: Theory, Design, and Characterization

Frequency Multiplier Based on Distributed Superconducting Tunnel Junctions: Theory, Design, and Characterization

Reduced resistance drift in tunnel junctions using confined tunnel barriers

Direct Measurement of Superconducting Tunnel Junction Capacitance

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