Superconducting properties and chemical composition of NbTiN thin films with different thickness

Zhang, L.; Peng, Wei; You, Lixing; Wang, Z.

doi:10.1063/1.4931943

Cited by 28 publications

(30 citation statements)

References 36 publications

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“…We observed a maximum resistivity of 3.61 μΩm with 5.4-nm-thick thin film, where the T c was 5.3K. The obtained resistivity was higher compared to that reported in other researches [18], [23], [24]. Although this could be caused by influence of the grain boundary and the crystallinity, it is still under investigation.…”

Section: Characteristics Of Nbtin Thin Filmscontrasting

confidence: 54%

Thermally Assisted Superconductor Transistors for Josephson-CMOS Hybrid Memories

Sano

Suzuki

Maruyama

et al. 2018

IEICE Trans. Electron.

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We have studied on thermally assisted nano-structured transistors made of superconductor ultra-thin films. These transistors potentially work as interface devices for Josephson-CMOS (complementary metal oxide semiconductor) hybrid memory systems, because they can generate a high output voltage of sub-V enough to drive a CMOS transistor. In addition, our superconductor transistors are formed with very fine lines down to several tens of nm in widths, leading to very small foot print enabling us to make large capacity hybrid memories. Our superconductor transistors are made with niobium titanium nitride (NbTiN) thin films deposited on thermally-oxidized silicon substrates, on which other superconductor circuits or semiconductor circuits can be formed. The NbTiN thickness dependence of the critical temperature and of resistivity suggest thermally activated vortex or anti-vortex behavior in pseudo-two-dimensional superconducting films plays an important role for the operating principle of the transistors. To show the potential that the transistors can drive MOS transistors, we analyzed the driving ability of the superconductor transistors with HSPICE simulation. We also showed the turn-on behavior of a MOS transistor used for readout of a CMOS memory cell experimentally. These results showed the high potential of superconductor transistors for Josephson-CMOS hybrid memories.

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Section: Characteristics Of Nbtin Thin Filmscontrasting

confidence: 54%

Thermally Assisted Superconductor Transistors for Josephson-CMOS Hybrid Memories

Sano

Suzuki

Maruyama

et al. 2018

IEICE Trans. Electron.

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“…2(c) selected area electron diffraction results are presented, showing a ring pattern typical for polycrystalline films. As can be seen in the inset, the [200] lattice spacing (obtained by azimuthal integration using the PASAD plug-in [22] and Digital Micrograph software) was found to scale with the Nb fraction x, which is expected for the fully miscible ternary NbTiN alloy [19]. We note that the lattice parameters were extracted from films grown on SiN TEM support films with a thickness of 10 nm, which most probably does not correspond to the lattice parameters of films deposited on SiO 2 /Si substrates due to different levels of microscopic strain [23].…”

Section: Superconducting Thin Film Deposition and Characterizationmentioning

confidence: 85%

“…In parallel, XPS measurements were performed to study the different compositions of the 50 nm films, using a PHI Quantera II Scanning ESCA microprobe with monochromatic Al Kα radiation and a spot size of 100 µm. The composition of the top surface, a native oxide layer as observed elsewhere [19], as well as the average bulk composition of the superconducting layer were determined. For the latter, 1 kV Ar + sputter etched depth profiles with an area of 1x1 mm 2 were conducted, the thickness of 50 nm allowing for the etching without removing the underlying NbTiN layer and for comparing values close to bulk conditions.…”

Section: Superconducting Thin Film Deposition and Characterizationmentioning

confidence: 99%

Optimizing the stoichiometry of ultrathin NbTiN films for high-performance superconducting nanowire single-photon detectors

Zichi¹,

Jin²,

Steinhauer³

et al. 2019

Opt. Express

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The requirements in quantum optics experiments for high single-photon detection efficiency, low timing jitter, low dark count rate and short dead time have been fulfilled with the development of superconducting nanowire single-photon detectors. Although they offer a detection efficiency above 90%, achieving a high time resolution in devices made of amorphous materials is a challenge, particularly at temperatures above 0.8 K. Devices made from niobium nitride and niobium titanium nitride allow us to reach the best timing jitter but, in turn, have stronger requirements in terms of film quality to achieve a high efficiency. Here we take advantage of the flexibility of reactive co-sputter deposition to tailor the composition of Nb x Ti 1-x N superconducting films and show that a Nb fraction of x = 0.62 allows for the fabrication of detectors from films as thick as 9 nm and covering an active area of 20 µm, with a wide detection saturation plateau at telecom wavelengths and in particular at 1550 nm. This is a signature of an internal detection efficiency saturation, achieved while maintaining the high time resolution associated with NbTiN and operation at 2.5K. With our optimized recipe, we reliably fabricated detectors with high critical current densities reaching a saturation plateau at 1550 nm with 80% system detection efficiency and with a FWHM timing jitter as low as 19.5 ps.

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“…We attribute this to the highly textured growth of NbTiN induced by the removal of the native amorphous oxide layer. We note that only this NbTiN thin film exhibited diffraction peaks in x-ray scans which can be attributed to a highly textured film with the (002) plane of the cubic phase oriented parallel to the substrate surface [28,29]. A detailed analysis of the x-ray diffraction of this sample has been added to the supplemental material (SM) (https://stacks.iop.org/MQT/2/015002/mmedia) section 1 [30].…”

Section: Methodsmentioning

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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Superconducting properties and chemical composition of NbTiN thin films with different thickness

Cited by 28 publications

References 36 publications

Thermally Assisted Superconductor Transistors for Josephson-CMOS Hybrid Memories

Thermally Assisted Superconductor Transistors for Josephson-CMOS Hybrid Memories

Optimizing the stoichiometry of ultrathin NbTiN films for high-performance superconducting nanowire single-photon detectors

Magnetic field robust high quality factor NbTiN superconducting microwave resonators

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