Thin-Film Nb/Polyimide Superconducting Stripline Flexible Cables

Gupta, Vaibhav; Yelamanchili, Bhargav; Zou, Simin; Isaacs-Smith, T.; Sellers, John A.; Tuckerman, David B.; Hamilton, Michael C.

doi:10.1109/tasc.2019.2904203

Cited by 15 publications

(5 citation statements)

References 16 publications

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“…Flexible superconducting wiring based on polyimide has been developed. Fabrication of superconducting wiring on polyimide ex requires 1) modi ed etching to create sloped sidewalls due to the relatively large thickness; 6.5 um in one case, 2) baking at 350 C that may modify critical LTD properties such transition temperatures or junction resistances, 3) seed layers to promote niobium adhesion and achieve good transition temperatures [15]- [17]. These additional fabrication requirements make polyimide ex di cult to integrate with active device fabrication.…”

Section: Comparison To Polyimide Flexmentioning

confidence: 99%

Flexible superconducting wiring for integration with low temperature detector and readout fabrication

O'Neil,

Doriese,

Keller

et al. 2023

Preprint

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We present a method of creating high-density superconducting flexible wiring on flexible thin silicon substrates. The flexible wiring, called SOI flex, is created by depositing superconducting wiring on a silicon on insulator (SOI) wafer, selectively etching away the thicker silicon section handle layer, and bending the thinner silicon device layer. We show measurements of superconducting transition temperature and critical current for Mo, Nb, and Al on SOI flex. We discuss the expected advantages of SOI flex for low-temperature detector applications, as well as the role of stress and strain in bent silicon and niobium.

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Section: Comparison To Polyimide Flexmentioning

confidence: 99%

Flexible superconducting wiring for integration with low temperature detector and readout fabrication

O'Neil,

Doriese,

Keller

et al. 2023

Preprint

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“…The MegaZOR was optimized to achieve less than 1 dB amplitude variation and less than 5 • phase variation between two chips with worst-case ±3% speed of light variation across the carrier and ±1% variation in resonance frequency between individual chips. The superconducting flexible ribbon cable has been designed at Auburn University [6,7] and fabricated by Hightec, a commercial manufacturer. The cable is a stack-up of thin-film polyimide layers (PI2611 from HD Microsystems) and patterned Nb metal.…”

Section: Test Vehiclementioning

confidence: 99%

“…This bandwidth-efficient driver has been used to demonstrate synchronous communication between 10×10 mm chips on an MCM with interconnect length up to 54 mm. Superconducting Nb flex tape on Polyimide has been proposed for board-toboard communication [6], [7]. Tape enables longer range communication relative to MCM because of very low dielectric losses, tan δ ≈ 10 −4 , at cryo temperatures [8] and due to relatively large dimensions for the traces and * This research is based upon work supported in part by the ODNI, IARPA, via ARO.…”

mentioning

confidence: 99%

Isochronous Data Link Across a Superconducting Nb Flex Cable with 5 femtojoules per Bit

Dai,

Kegerreis,

Gamage

et al. 2021

Preprint

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Interconnect properties position superconducting digital circuits to build large, high performance, power efficient digital systems. We report a board-to-board communication data link, which is a critical technological component that has not yet been addressed. Synchronous communication on chip and between chips mounted on a common board is enabled by the superconducting resonant clock/power network for RQL circuits. The data link is extended to board-to-board communication using isochronous communication, where there is a common frequency between boards but the relative phase is unknown. Our link uses over-sampling and configurable delay at the receiver to synchronize to the local clock phase. A single-bit isochronous data link has been demonstrated onchip through a transmission line, and on a multi-chip module (MCM) through a superconducting tape between driver and receiver with variable phase offset. Measured results demonstrated correct functionality with a clock margin of 3 dB at 3.6 GHz, and with 5 fJ/bit at 4.2 K.Superconducting digital circuits have the potential to enable digital systems with very high computation density [1]. The combination of low power logic [2] and low loss interconnects (e.g. [3] and references thereof) shifts the design trade-off towards heterogeneous distributed architectures with multiple chips on multiple boards. Volumetric cooling with efficient heat transfer allows such a system to be physically small, with packing density limited only by the physical dimensions of the connectors on the boards. Superconducting systems trade modest chip integration density for high packaging density.Efficient distributed heterogeneous architectures require tremendous communication bandwidth on-board and board-to-board. Design challenges involve both the interconnects themselves, and synchronization between driver and receiver. Nb interconnects having 700 GHz analog bandwidth can cover distance with appropriate data encoding and geometry of the wires [4]. A bandwidth-efficient driver producing 10 SFQ pulses per bit, with an analog bandwidth of 35 GHz and 0.58 fJ per bit has been reported in [5]. This bandwidth-efficient driver has been used to demonstrate synchronous communication between 10×10 mm chips on an MCM with interconnect length up to 54 mm. Superconducting Nb flex tape on Polyimide has been proposed for board-toboard communication [6], [7]. Tape enables longer range communication relative to MCM because of very low dielectric losses, tan δ ≈ 10 −4 , at cryo temperatures [8] and due to relatively large dimensions for the traces and * This research is based upon work supported in part by the ODNI, IARPA, via ARO. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the ODNI, IARPA, or the U.S. Government.

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“…These technologies range from radiation detectors, such as superconducting nanowire single-photon detectors (SNSPD) [1,2] and microwave kinetic inductance detectors (MKIDs) [3], to Josephson junctions [4,5], transmission lines, and coatings for superconducting radiofrequency cavities (SRF) [6][7][8], among others. In addition to rigid devices, flexible substrates could enhance performance in many applications, allowing the superconductor film to withstand mechanical deformation [9][10][11][12][13][14]. The selection of materials for technological devices typically depends on properties such as the superconducting gap (Δ), penetration depth (λ), coherence length (ξ), critical fields, and depairing critical current density (J 0 ) [15].…”

Section: Introductionmentioning

confidence: 99%

Penetration depth and critical fields in superconducting NbTi thin films grown by co-sputtering at room temperature

Lee,

Yun,

Lee

et al. 2024

Phys. Scr.

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We present a study on the superconducting properties of 300 nm thick NbTi thin films grown by co-sputtering on silicon substrates at room temperature. The samples exhibit a Nb (50 at.%) and Ti (50 at.%) chemical composition, revealing a polycrystalline structure textured along the (110) axis of the body-centered cubic structure. The measured superconducting critical temperature (Tc ) was 9.65 K, and the upper critical field extrapolated to zero temperature reached approximately 15 T, resulting in a coherence length at zero temperature of approximately 4.7 nm. The penetration depth was determined through local magnetic force microscopy measurements conducted at temperatures from 4.25 to 7 K. The obtained values ranges from 250 (15) nm at 4.25 K to 370 (20) nm at 7 K. Extrapolating these measurements to zero temperature, we obtained an estimated value of 230 (20) nm. To extend the performance and potential applications of NbTi, we additionally grew a 150 nm thick sample on flexible polyimide. In this case, we observed that the films preserved their superconducting properties, displaying a decrease in Tc to 9.2 K and a similar upper critical field compared to samples grown on silicon. The feasibility of growing NbTi alloys at room temperature, with superconducting parameters comparable to or superior to metallic Nb for the upper critical field, renders this system promising for cryogenic applications, particularly in the development of high-performance electronic devices on both rigid and flexible substrates.

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Thin-Film Nb/Polyimide Superconducting Stripline Flexible Cables

Cited by 15 publications

References 16 publications

Flexible superconducting wiring for integration with low temperature detector and readout fabrication

Flexible superconducting wiring for integration with low temperature detector and readout fabrication

Isochronous Data Link Across a Superconducting Nb Flex Cable with 5 femtojoules per Bit

Penetration depth and critical fields in superconducting NbTi thin films grown by co-sputtering at room temperature

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