Superconducting Characteristics of NbN Films Deposited by Atomic Layer Deposition

Ukibe, Masahiro; Fujii, Go

doi:10.1109/tasc.2017.2655719

Cited by 13 publications

(12 citation statements)

References 14 publications

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“…S4-A exhibits the lowest Tc value (10.1 K). The evolution of the Tc of all our samples with annealing differs from that of several previously published results, where it is shown that annealing lowers the Tc [19,31]. Other publications show that annealing between 800 and 1000 ° C increases the Tc of the NbN samples [32][33][34].…”

Section: Critical Temperaturecontrasting

confidence: 91%

“…shows that the density of the samples increased after annealing and S2 exhibited the highest density among all of the samples. existing information in previous studies on the ALD synthesis of NbN [14][15][16][17][18][19], the presence of carbon as an impurity in the classical ALD process could significantly impact the superconductivity. Therefore, the improvement of the Tc of our carbon-free samples after annealing is related to another parameter.…”

Section: Effect Of Annealing In Argonmentioning

confidence: 99%

“…Extremely interesting results (Tc: ~14 K for the ~30 nm thick film) have been reported using TBTDEN/H 2 [15,18] or TBTDEN/H 2 /N 2 [17,19]. Several authors [14,18] reported that the films may contain relatively high amounts of oxygen and carbon, up to 50 at%.…”

Section: Introductionmentioning

confidence: 97%

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Improved critical temperature of superconducting plasma-enhanced atomic layer deposition of niobium nitride thin films by thermal annealing

et al. 2020

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The efficiency of the superconducting radio frequency cavities composed of Nb required the deposition of thickness-controlled multilayer coatings of superconductor-insulator-superconductor (S-IS) on the internal surfaces of the cavities. Herein, we report the plasma-enhanced atomic layer deposition of carbon-free NbN (50 µm thick), followed by a thermal treatment, to obtain the superconducting layer in the S-IS structure. Using (tert-butylimido)-tris(diethylamino)-niobium as the niobium precursor and H 2 and NH 3 plasma as reactive gases, the deposition and annealing parameters were optimized by studying their effects on the film properties (crystallinity, density, and composition). We demonstrated that the superconducting critical temperature (Tc) can be improved after thermal annealing up to 13.8 K, a value compatible with the targeted application. In addition to the expected densified layers and increased grain size, we observed a partial transformation of the oxide present in the as-deposited layer into niobium oxynitride, which could indicate the origin of the improvement of the superconducting properties. With low carbon and oxygen impurity concentrations in the films, this study contributes to the understanding of the relationship between the structure, composition, and superconductivity in NbN.

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Section: Critical Temperaturecontrasting

confidence: 91%

Section: Effect Of Annealing In Argonmentioning

confidence: 99%

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Improved critical temperature of superconducting plasma-enhanced atomic layer deposition of niobium nitride thin films by thermal annealing

et al. 2020

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“…The superconducting transition temperature (Tc) and the superconducting transition width (ΔT) have measured values of 11.2 K and 0.24 K, respectively. Here, Tc is defined at 10%R (R is the resistance of the normal state at 20 K), and ΔT is the temperature interval between 90%R and 10%R 17 . Meanwhile, the test results are shown in Fig.…”

Section: Fabrication Of Nbn Nanowiresmentioning

confidence: 99%

Fabrication of superconducting niobium nitride nanowire with high aspect ratio for X-ray photon detection

Guo

Chen

Pan

et al. 2020

Sci Rep

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The niobium nitride (NbN) nanowires fabricated with the high-quality ultra-thin NbN film with a thickness of 3 nm-6 nm were widely used for single photon detectors. These nanowires had a low aspect ratio, less than 1:20. However, increasing the thickness and the aspect ratio of highly-uniformed NbN nanowires without reducing the superconductivity is crucial for the device in detecting high-energy photons. In this paper, a high-quality superconducting nanowire with aspect ratio of 1:1 was fabricated with optimized process, which produced a superconducting critical current of 550 μA and a hysteresis of 36 μA at 2.2 K. With the optimization of the electron beam lithography process of AR-P6200.13 and the adjustion of the chamber pressure, the discharge power, as well as the auxiliary gas in the process of reactive ion etching (RIE), the meandered NbN nanowire structure with the minimum width of 80 nm, the duty cycle of 1:1 and the depth of 100 nm were finally obtained on the silicon nitride substrate. Simultaneously, the sidewall of nanowire was vertical and smooth, and the corresponding depth-width ratio was more than 1:1. The fabricated NbN nanowire will be applied to the detection of soft X-ray photon emitted from pulsars with a sub-10 ps time resolution. Niobium nitride (NbN) has been widely studied in superconductor electronics for high superconducting transition temperature (up to 16 K), critical current density and critical magnetic field 1. Moreover, the corresponding physical properties were stable, and it could have large scale with high quality. Also, it was the most common materials to fabricate the superconducting nanowire single-photon detectors (SNSPDs) 2,3 , the mixer of Terahertz wave detection hot-electron-bolometer (HEB) 4 , and the superconducting quantum interference device (SQUID). At present, the preparation of SNSPDs mainly use the epitaxial method to grow the high-quality ultra-thin NbN film with a thickness of 3-6 nm. Then, the film is prepared to the meandered nanowire structure by means of micro-nano processing. The width of NbN nanowire is about 100 nm, and the aspect ratio is generally lower than 1:20. Considering the advantages of SNSPDs, such as the low dark count, the wide response spectrum, the short recovery time and the high time precision, SNSPDs were widely studied and applied to the detection of visible/ infrared single photon 5. However, the application of SNSPDs in the direction of high-energy photon (UV, X-ray, and gamma ray) was rarely studied for low absorption of ultra-thin NbN films with the high-energy photons 6-8. Through Geant4 simulations, we obtained that the X-ray photon absorption of the 10 nm thick NbN film for 1 keV and 6 keV was only 3.69% and 0.23%, respectively 9 , and the SNSPD prepared with the ultra-thin NbN film was unable to effectively detect high-energy single photons. The simulation results show that the absorption of 1 keV and 6 keV by NbN with a 100 nm film thickness are 31.31% and 2.25%, respectively. To improve the absorption of superconducting NbN...

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“…Josephson junctions, which are central elements in superconducting electronics, can be made by synthesizing superconducting films with a thin layer of non-superconducting material sandwiched in-between, e.g. trilayers of NbN-AlN-NbN [4,5], and they can be used for applications such as tunnel junction particle detectors [6] and in single fluxquantum circuits [7]. Flux pinning forces and critical current density can be increased by having many alternating layers of NbN and AlN in one sample [8].…”

Section: History and Motivationmentioning

confidence: 99%

Characterization of <inline-formula> <tex-math notation="LaTeX">${YBa}_{2}{Cu}_{3}{O}_{7-\delta}$</tex-math> </inline-formula> Films With Various Porous Structures Grown by Metalorganic Decomposition Route

Zhao

Qureishy

Mikheenko

et al. 2016

IEEE Trans. Appl. Supercond.

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Superconducting Characteristics of NbN Films Deposited by Atomic Layer Deposition

Cited by 13 publications

References 14 publications

Improved critical temperature of superconducting plasma-enhanced atomic layer deposition of niobium nitride thin films by thermal annealing

Improved critical temperature of superconducting plasma-enhanced atomic layer deposition of niobium nitride thin films by thermal annealing

Fabrication of superconducting niobium nitride nanowire with high aspect ratio for X-ray photon detection

Characterization of <inline-formula> <tex-math notation="LaTeX">${YBa}_{2}{Cu}_{3}{O}_{7-\delta}$</tex-math> </inline-formula> Films With Various Porous Structures Grown by Metalorganic Decomposition Route

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