On-chip integrable planar NbN nanoSQUID with broad temperature and magnetic-field operation range

Holzman, Itamar; Ivry, Yachin

doi:10.1063/1.5100259

Cited by 10 publications

(11 citation statements)

References 64 publications

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“…From a material point of view, Nb [27], Al [28], NbN [29,30], MoRe [13] are typically used for temperatures T > 1 K. MoRe film was magnetron sputtered on the Si − SiO 2 substrate; 3) e-resist was spun and after e-beam exposition 4) and developing, the resist mask 5) was formed; 6) the Al was deposited; 7) lift-off of the resist with Al film on it; 8) MoRe plasma etching; 9) Al hard mask etching.…”

Section: Introductionmentioning

confidence: 99%

Planar MoRe-based direct current nanoSQUID

Shishkin

Skryabina

Гуртовой

et al. 2020

Supercond. Sci. Technol.

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We have developed planar nanoSQUID with nanobridge-type Josephson junctions based on the oxidation resistant and high H c2 MoRe alloy. The objective of the research was to reduce size of the SQUID loop with the aim being to reduce magnetic flux noise and improve the spatial resolution of the SQUID sensors. Employing RF-magnetron sputtering, electron-beam lithography, and reactive ion etching in CHF 3 + O 2 plasma using Al hard masks, we have realized nanoSQUIDs with Josephson junctions in the form of 30 − 50 nm wide nanobridges and an effective magnetic flux capture radius of ~95 nm. The critical temperature of the fabricated devices was T c = 7.9 K. The I(V)-characteristics demonstrated critical current I 0 ≃ 114 µA at 4.2 K and modulation period in magnetic fields of ~700 Oe.

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Section: Introductionmentioning

confidence: 99%

Planar MoRe-based direct current nanoSQUID

Shishkin

Skryabina

Гуртовой

et al. 2020

Supercond. Sci. Technol.

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“…To demonstrate the direct effect of polarization reversal on the behavior of a SQUID, a planar SQUID was fabricated as illustrated in Figure 3 (see Reference 35 for details related to device fabrication). Figure 4 shows that a negative polarization in the ferroelectric resulted in 𝐼 c = 4.0±0.03 A, and 𝐼 c = 2.6±0.03 A for positive polarization (measured at 3 K).…”

Section: Fig 2 Voltage-tunable Superconductive-ferroelectric Device (A)mentioning

confidence: 99%

“…Table1shows that the extracted 𝛿𝑛 e is in agreement with the expected value, where it also presents the extracted coherence length 𝜉 = This is the author's peer reviewed, accepted manuscript. However, the online version of record will be different from this version once it has been copyedited and typeset.PLEASE 𝑣 F ≈ 3 • 10 4 m s -1 for molybdenum silicide 40 and ℏ is the reduced Planck's constant), SQUID's , (𝐿 = 8.035 * 10 −10 [H] is the device inductance and Φ 0 is magnetic flux quantum)16,35 for the two polarization states.…”

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confidence: 99%

Nonvolatile voltage-tunable ferroelectric-superconducting quantum interference memory devices

Suleiman

Sarott

Trassin

et al. 2021

Applied Physics Letters

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Superconductivity serves as a unique solid-state platform for electron interference at a devicerelevant lengthscale, which is essential for quantum information and sensing technologies. As opposed to semiconducting transistors that are operated by voltage biasing at the nanometer scale, superconductive quantum devices cannot sustain voltage and are operated with magnetic fields, which impose a large device footprint, hindering miniaturization and scalability. Here we introduce a system of superconducting materials and devices that have a common interface with a ferroelectric layer. An amorphous superconductor was chosen for reducing substrate-induced misfit strain and for allowing low-temperature growth. The common quantum pseudowavefunction of the superconducting electrons was controlled by the non-volatile switchable polarization of the ferroelectric by means of voltage biasing. A controllable change of 21% in the critical temperature was demonstrated for a continuous film geometry. Moreover, a controllable change of 54% in the switching current of a superconducting quantum interference device (SQUID) was demonstrated. The ability to voltage bias superconducting devices together with the non-volatile nature of this system paves the way to quantum-based memory devices.

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“…Thin films of NbN and MoRe have relatively large energy gaps 2∆ ~5 meV. However, their T c values of up to ~16 K and their very short coherence lengths ξ of ~5 nm lead to difficulties in the realization of non-hysteretic nanoSQUIDs with nJJs at an operation temperature of 4.2 K [22][23][24]. NJJs and nanoSQUIDs that are based on nJJs can have hysteretic I(V) characteristics, as a result of (1) the effect of nJJ overheating hysteresis [7,25], or (2) an ambiguity in the I(ϕ) characteristics of nJJs [25,26] in the case of large nJJs when their length is >3.5 ξ [26].…”

Section: Introductionmentioning

confidence: 99%

“…Two methods are usually used to pattern nanostructures of TiN, NbN, and Nb: electron beam lithography (EBL) in combination with reactive ion etching (RIE) [7,24,25] and focused ion beam (FIB) milling [25,29]. The high selectivity and isotropy of RIE allow the realization of variable thickness nJJs down to 10 nm resolution [7], but these are sensitive to sample temperature and surface contamination, to the configuration of nearby current leads, and to the granular structure of the etched film, as well as previous processes in the RIE machine: the etch rate of a second sample can then be lower than the etch rate of a first sample.…”

Section: Introductionmentioning

confidence: 99%

A Self-Flux-Biased NanoSQUID with Four NbN-TiN-NbN Nanobridge Josephson Junctions

Faley

Dunin-Borkowski

2022

Electronics

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We report the development of a planar 4-Josephson-junction nanoscale superconducting quantum interference device (nanoSQUID) that is self-biased for optimal sensitivity without the application of a magnetic flux of Φ0/4. The nanoSQUID contains novel NbN-TiN-NbN nanobridge Josephson junctions (nJJs) with NbN current leads and electrodes of the nanoSQUID body connected by TiN nanobridges. The optimal superconducting transition temperature of ~4.8 K, superconducting coherence length of ~100 nm, and corrosion resistance of the TiN films ensure the hysteresis-free, reproducible, and long-term stability of nJJ and nanoSQUID operation at 4.2 K, while the corrosion-resistant NbN has a relatively high superconducting transition temperature of ~15 K and a correspondingly large energy gap. FIB patterning of the TiN films and nanoscale sculpturing of the tip area of the nanoSQUID’s cantilevers are performed using amorphous Al films as sacrificial layers due to their high chemical reactivity to alkalis. A cantilever is realized with a distance between the nanoSQUID and the substrate corner of ~300 nm. The nJJs and nanoSQUID are characterized using Quantum Design measurement systems at 4.2 K. The technology is expected to be of interest for the fabrication of durable nanoSQUID sensors for low temperature magnetic microscopy, as well as for the realization of more complex circuits for superconducting nanobridge electronics.

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On-chip integrable planar NbN nanoSQUID with broad temperature and magnetic-field operation range

Cited by 10 publications

References 64 publications

Planar MoRe-based direct current nanoSQUID

Planar MoRe-based direct current nanoSQUID

Nonvolatile voltage-tunable ferroelectric-superconducting quantum interference memory devices

A Self-Flux-Biased NanoSQUID with Four NbN-TiN-NbN Nanobridge Josephson Junctions

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