Fabrication of Niobium Titanium Nitride Thin Films With High Superconducting Transition Temperatures and Short Penetration Lengths

Yu, Lei; Singh, Rakesh Kumar; Liu, Hongxue; Wu, Stephen Y.; Hu, R.; Durand, D.J.; Bulman, J.B.; Rowell, J. M.; Newman, Nathan

doi:10.1109/tasc.2005.844126

Cited by 29 publications

(24 citation statements)

References 17 publications

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“…This is successfully applied to the NbTiN and NbN films. [10,11] Although this technique is very effective, it would sometimes restrict the HEB device fabrication process. For instance, the lift-off process is difficult to be applied, because the resist cannot survive in good conditions at very high temperature.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the critical temperature of superconducting NbTiN and NbN thin films using the AlN buffer layer

Shiino

Shiba

Sakai

et al. 2010

Supercond. Sci. Technol.

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Thin superconducting NbTiN and NbN films with a few nm thickness are used for various device applications including hot electron bolometer mixers. Such thin films have lower critical temperature (T c) and higher resistivity than corresponding bulk materials. To improve them, we have investigated an effect of the AlN buffer layer between the film and the substrate (quartz or soda lime glass). The AlN film is deposited by DC magnetron sputtering, and the process condition is optimized so as that the X-ray diffraction intensity from the 002 surface of Wurtzite AlN becomes highest. By use of this well-characterized buffer layer, T c and resistivity of the NbTiN film with a few nm thickness are remarkably increased and decreased, respectively, in comparison with those without the buffer layer. More importantly, the AlN buffer layer is found to be effective for NbN. With the AlN buffer layer, T c is increased from 7.3 K to 10.5 K for the 8 nm NbN film. The improvement of T c and resistivity originates Improvement of T c of NbTiN and NbN Thin Films Using the AlN Buffer Layer 2 from the good lattice matching between the 002 surface of AlN and the 111 surface of NbTiN or NbN, which makes better crystallization of the NbTiN or NbN film. This is further confirmed by the X-ray diffraction measurement.

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Section: Introductionmentioning

confidence: 99%

Improvement of the critical temperature of superconducting NbTiN and NbN thin films using the AlN buffer layer

Shiino

Shiba

Sakai

et al. 2010

Supercond. Sci. Technol.

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“…We make use of this and fit equation ( 2) to the data presented in figure 3(a) to extract α = 0.124 ± 0.001. Here, we assume that λ L (T) = λ L (0)/ 1 − (T/T c ) 4 [42], with λ L (0) = 200 nm [24] and T c = 16.3 ± 0.1 K, which was determined by recording S 21 (T) while raising the sample temperature (see section 3 of the SM [30]). This value of α falls into the expected range for planar 2D-resonators (10 −2 α 1) [43][44][45].…”

Section: Performance Of Nbtin Resonators At Elevated Temperatures For...mentioning

confidence: 99%

“…Niobium titanium nitride (NbTiN) is one of the prime candidates, as it is a hard type II superconductor with a transition temperature of up to T c = 17 K [21][22][23] and a large Ginzburg-Landau parameter κ GL > 50 (κ GL = λ L /ξ GL , where λ L is the London penetration depth and ξ GL is the superconducting Ginzburg-Landau coherence length. For NbTiN, we assume λ NbTiN L = 200 nm [24] and ξ NbTiN GL = 3.8 nm [25]). The higher T c typically translates into a larger superconducting gap and the large κ GL into a high upper critical field.…”

Section: Introductionmentioning

confidence: 99%

Magnetic field robust high quality factor NbTiN superconducting microwave resonators

Müller

Luschmann

Faltermeier

et al. 2022

Mater. Quantum. Technol.

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We systematically study the performance of compact lumped element planar microwave $\mathrm{Nb_{70}Ti_{30}N}$ (NbTiN) resonators operating at 5 GHz in external in-plane magnetic fields up to 440 mT, a broad temperature regime from 2.2 K up to 13 K, as well as mK temperatures. For comparison, the resonators have been fabricated on thermally oxidized and pristine, (001) oriented silicon substrates. When operating the resonators in the multi-photon regime at $T=2.2$ K, we find internal quality factors $Q_{\mathrm{int}}\simeq$ $2\cdot10^5$ for NbTiN resonators grown on pristine Si substrates. In addition, we investigate the $Q$-factors of the resonators on pristine Si substrates at millikelvin temperatures to asses their applicability for quantum applications. We find $Q_{\mathrm{int}}\simeq$ $2\cdot10^5$ in the single photon regime and $Q_{\mathrm{int}}\simeq$ $5\cdot10^5$ in the high power regime at $T=7$ mK. From the excellent performance of our resonators over a broad temperature and magnetic field range, we conclude that NbTiN deposited on Si (100) substrates, where the suface oxide has been removed, constitutes a promising material platform for electron spin resonance and ferromagnetic resonance experiments using superconducting planar microwave resonators.

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“…Niobium titanium nitride (NbTiN) is one of the prime candidates, as it is a hard type II superconductor with a transition temperature of up to T c = 17 K [30][31][32] and a large Ginzburg-Landau parameter κ GL > 50 (κ GL = λ L /ξ GL , where λ L is the London penetration depth and ξ GL is the superconducting Ginzburg-Landau coherence length. For NbTiN, we assume λ NbTiN L = 200 nm [33] and ξ NbTiN GL = 3.8 nm [34]). The higher T c typically translates into a larger superconducting gap and the large κ GL into a high upper critical field.…”

Section: Introductionmentioning

confidence: 99%

Magnetic field robust high quality factor NbTiN superconducting microwave resonators

Müller,

Luschmann,

Faltermeier

et al. 2021

Preprint

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We systematically study the performance of compact lumped element planar microwave Nb 70 Ti 30 N (NbTiN) resonators operating at 5 GHz in external in-plane magnetic fields up to 440 mT, a broad temperature regime from 2.2 K up to 13 K, as well as mK temperatures. For comparison, the resonators have been fabricated on thermally oxidized and pristine, (001) oriented silicon substrates. When operating the resonators in the multi-photon regime at T = 2.2 K, we find internal quality factors Q int 2 • 10 5 for NbTiN resonators grown on pristine Si substrates, while resonators grown on thermally oxidized substrates show a reduced value of Q int 1 • 10 4 , providing evidence for additional loss channels for the latter substrate. In addition, we investigate the Q-factors of the resonators on pristine Si substrates at millikelvin temperatures to asses their applicability for quantum applications. We find Q int 2 • 10 5 in the single photon regime and Q int 5 • 10 5 in the high power regime at T = 7 mK.

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Fabrication of Niobium Titanium Nitride Thin Films With High Superconducting Transition Temperatures and Short Penetration Lengths

Cited by 29 publications

References 17 publications

Improvement of the critical temperature of superconducting NbTiN and NbN thin films using the AlN buffer layer

Improvement of the critical temperature of superconducting NbTiN and NbN thin films using the AlN buffer layer

Magnetic field robust high quality factor NbTiN superconducting microwave resonators

Magnetic field robust high quality factor NbTiN superconducting microwave resonators

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