TaN Nanowire Thermal Performance with Copper Integration

Scientists achieved significant advancements in superconducting nanowire technology by fabricating tantalum nitride (TaN) and TaN/copper (TaN/Cu) bilayer nanowires on 300 mm silicon wafers using processes compatible with standard CMOS manufacturing. The research focused on quantifying how integrating a copper heatsink modifies the superconducting response of TaN nanowires, with the goal of improving thermal dissipation without compromising superconducting characteristics. Experiments revealed a substantial improvement in heat dissipation with the Cu integration, supporting expectations of faster reset times crucial for superconducting nanowire single‑photon detectors (SNSPDs). Data shows that the incorporation of copper resulted in approximately a 100× increase in the Skocpol‑Beasley‑Tinkham (SBT) slope parameter β and effective interfacial heat‑transfer efficiency when compared to standalone TaN nanowires.

Measurements confirm a near‑unity ratio of critical current to retrapping current in the TaN/Cu bilayer nanowires, providing further evidence of the efficient heat removal facilitated by the integrated copper layer. The team measured a zero‑temperature Ginzburg‑Landau coherence length of 7 nm and a critical temperature of 4.1 K for 39 nm thick TaN nanowires, establishing baseline superconducting properties. Tests prove exceptional process uniformity and scalability, with the nanowires exhibiting less than 5 % variation in critical dimensions, room‑temperature resistance, residual‑resistance ratio, critical temperature, and critical current across the entire 300 mm wafer for all measured linewidths. Results demonstrate the trade‑offs between superconducting performance and heat‑sinking efficiency in the TaN/Cu bilayer nanowires, offering valuable insights for device optimisation. This work underscores the viability of wafer‑scale fabrication for creating fast, large‑area SNSPD arrays, opening possibilities for applications in photonic quantum computing, cosmology, and neuromorphic computing devices.

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TaN Bilayer Nanowires Enhance Heat Dissipation

This work demonstrates a fully CMOS‑compatible process for fabricating ultrathin tantalum nitride (TaN) nanowires and TaN/copper (TaN/Cu) bilayer nanowires on 300 mm silicon wafers, achieving excellent uniformity in critical dimensions and superconducting properties. Researchers successfully integrated copper as a heat sink to improve thermal dissipation in the TaN nanowires, evidenced by a significant enhancement in heat‑transfer efficiency—approximately 100 × greater than that of TaN nanowires alone—and a near‑unity ratio of critical to retrapping current in the bilayer structures. The findings establish a clear link between material integration and improved performance metrics relevant to SNSPDs, suggesting potential for faster reset times. Authors quantified these improvements using the Skocpol‑Beasley‑Tinkham hotspot model, revealing a substantial increase in the slope parameter β and effective interfacial heat‑transfer efficiency.

The authors acknowledge limitations related to optimizing TaN/Cu geometries, noting that future work will explore varying thicknesses to further refine performance and build on the demonstrated process control and tunability of superconducting and thermal properties for advanced quantum photonic and sensing technologies. The pursuit of efficient superconductivity at larger scales remains a significant challenge in developing advanced detectors and quantum technologies. This enhancement is particularly important for SNSPDs, promising faster reset times and improved detection capabilities. By quantifying improvements in heat transfer using established models, the team highlights the potential for scalable, wafer‑scale fabrication of high‑performance SNSPD arrays for applications ranging from quantum computing to cosmology.

Researchers report on the superconducting properties of tantalum nitride (TaN) nanowires and TaN/copper (TaN/Cu) bilayer nanowires fabricated on 300 mm silicon wafers utilizing CMOS‑compatible processes. The study evaluates the impact of an integrated copper heatsink on the superconducting response of TaN nanowires, specifically examining improvements in thermal dissipation. Investigations focus on whether this thermal enhancement compromises critical superconducting parameters such as critical temperature and critical current density. Analysis of hysteresis in current‑voltage characteristics provides insight into the superconducting behaviour of these nanowire structures. The work demonstrates a pathway to optimise nanowire superconducting performance through integrated thermal‑management techniques.