Superconducting properties of NbTiN thin films deposited by high-temperature chemical vapor deposition

Hazra, Dibyendu; Tsavdaris, Nikolaos; Mukhtarova, Anna; Jacquemin, Manoël; Blanchet, Florian; Albert, Romain; Jebari, Salha; Grimm, Alexander; Konar, Aniruddha; Blanquet, Elisabeth; Mercier, F.; Chapelier, Claude; Hofheinz, M.

doi:10.1103/physrevb.97.144518

Cited by 22 publications

(30 citation statements)

References 45 publications

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“…The Ti fraction x = 0.3 in Set-1 and Set-2 and x = 0.33 in Set-3. Films within single Set are grown varying the number of ALD cycles, that provides films of different thickness d. The parameters of samples are given in the Table. The Hall carrier density n (see SI) appears to be approximately the same regardless of the disorder n ∼ 10 22 cm −3 which is one order smaller that in NbTiN films examined in 24 . Figure 1 presents the temperature dependencies of the sheet resistance R ✷ for three our Sets of films.…”

Section: Samples Preparation and Characterizationmentioning

confidence: 81%

Superconducting phase transitions in disordered NbTiN films

Burdastyh

Postolova

Proslier

et al. 2020

Sci Rep

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The suppression of superconductivity in disordered systems is a fundamental problem of condensed matter physics. Here we investigate the superconducting niobium-titanium-nitride (Nb 1−x TixN) thin films grown by atomic layer deposition (ALD) where disorder is controlled by the slight tuning of the ALD process parameters. We observe the smooth crossover from the disorderdriven superconductor-normal metal transition (often reffered to as fermionic mechanism) to the case where bosonic mechanism dominates and increasing disorder leads to formation of metal with Cooper pairing. We show that, in 'moderately' disordered films, the transition to zero-resistance state occurs in a full agreement with the conventional theories of superconducting fluctuations and Berezinskii-Kosterlitz-Thouless transition. However, the 'critically' disordered films violate this accord showing low-temperature features possibly indicating the Bose metal phase. We show that it is the interrelation between film's sheet resistance in the maximum, Rmax, of the resistive curve R✷(T ) and Rq = h/4e 2 that distinguishes between these two behaviors. We reveal the characteristic features in magnetoresistance of the 'critically' disordered films with Rmax > Rq. 2/9

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Section: Samples Preparation and Characterizationmentioning

confidence: 81%

Superconducting phase transitions in disordered NbTiN films

Burdastyh

Postolova

Proslier

et al. 2020

Sci Rep

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“…We fixed other parameters such as k F , l e , and N (0) to their values given in Table I and adopted for m e the value of the free-electron mass. We implemented the lattice parameter a 0 = 0.43 nm [33][34][35], the sound velocity of longitudinal phonons u l = 2u t that is approximately valid for a large variety of materials, and k ∼ 1.0 (Appendix B). The best-fit values of u t and ρ are listed in Table III.…”

Section: B Magnetoconductancementioning

confidence: 99%

Magnetoconductance and photoresponse properties of disordered NbTiN films

et al. 2021

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We report on the experimental study of phonon properties and electron-phonon scattering in thin superconducting NbTiN films, which are intensively exploited in various applications. Studied NbTiN films with sub-10-nm thicknesses are disordered with respect to electron transport, the Ioffe-Regel parameter of kFle=2.5-3.0 (kF is the Fermi wave vector, and le is the electron mean free path), the inelastic electron-phonon interaction, and the product qTle1 (qT is the wave vector of a thermal phonon). By means of magnetoconductance and photoresponse techniques, we derive the inelastic electron-phonon scattering rate 1/e-ph and determine sound velocities and phonon heat capacities. In the temperature range from 12 to 20 K, the scattering rate varies with temperature as 1/e-phT3.45±0.05; its value extrapolated to 10 K amounts to approximately 1/16 ps. Making a comparative analysis of our films and other films used in superconducting devices, such as polycrystalline granular NbN and amorphous WSi, we find a systematic reduction of the sound velocity in all these films by about 50% compared to the corresponding bulk crystalline materials. A corresponding increase in the phonon heat capacities in all these films is, however, less than the Debye model predicts. We attribute these findings to reduced film dimensionality and film morphology.

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“…4. The specific inductance and the corresponding film thickness of various materials including TAN (this work), TiN [20,23,43], NbTiN [17,18,24], NbN [25], and granular aluminum [14][15][16]39]. The granular aluminum has a wide range of reported values and is indicated by the shaded area.…”

Section: Discussionmentioning

confidence: 99%

“…Owing to the low energy dissipation, resilience to magnetic fields, and process compatibility, these emerging materials are advantageous for high-coherence applications and large-scale circuit integration [17][18][19][20][21]. Nevertheless, due to the relatively small kinetic inductance (i.e., on the order of picohenry-per-square), a nanowire with large aspect ratio is inevitably required for the implementation of highinductance elements [22][23][24][25][26]. Any imperfection of the nanowire could be a source of energy dissipation and deteriorate the circuit coherence.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, thin films of TiN or NbN have been shown to yield a sheet inductance of several hundred picohenry-persquare as the film is thinner than 10 nm [20,23,27,28]. The chemical and structural disorder in NbTiN can also be increased if the deposition techniques and parameters are properly refined [24,29]. However, despite the continuing optimization in the material synthesis, it remains a fundamental challenge to control the homogeneity of ultrathin films where a slight variation in thickness will inevitably result in substantial changes in the material properties.…”

Section: Introductionmentioning

confidence: 99%

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Ultrahigh-inductance materials from spinodal decomposition

Gao,

Ku,

Deng

et al. 2021

Preprint

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Disordered superconducting nitrides with kinetic inductance have long been considered a leading material candidate for high-inductance quantum-circuit applications. Despite continuing efforts in reducing material dimensions to increase the kinetic inductance and the corresponding circuit impedance, it becomes a fundamental challenge to improve further without compromising material qualities. To this end, we propose a method to drastically increase the kinetic inductance of superconducting materials via spinodal decomposition while keeping a low microwave loss. We use epitaxial Ti0.48Al0.52N as a model system, and for the first time demonstrate the utilization of spinodal decomposition to trigger the insulator-to-superconductor transition with a drastically enhanced material disorder. The measured kinetic inductance has increased by 2-3 orders of magnitude compared with all the best reported disordered superconducting nitrides. Our work paves the way for substantially enhancing and deterministically controlling the inductance for advanced superconducting quantum circuits.

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Superconducting properties of NbTiN thin films deposited by high-temperature chemical vapor deposition

Cited by 22 publications

References 45 publications

Superconducting phase transitions in disordered NbTiN films

Superconducting phase transitions in disordered NbTiN films

Magnetoconductance and photoresponse properties of disordered NbTiN films

Ultrahigh-inductance materials from spinodal decomposition

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