Tantalum Nitride Nanowires Achieve 100x Heat Transfer Improvement with Integrated Heatsinking

The pursuit of efficient superconductivity at larger scales remains a significant challenge in developing advanced detectors and quantum technologies. Ekta Bhatia, Tharanga R. Nanayakkara, and Chenyu Zhou, alongside colleagues from NY Creates and Brookhaven National Laboratory, have investigated the superconducting properties of tantalum nitride nanowires, exploring how integrated heatsinking impacts performance on 300mm silicon wafers. Their research demonstrates that incorporating a copper heatsink substantially improves thermal dissipation within these nanowires, without detrimentally affecting crucial superconducting characteristics. This enhancement is particularly important for superconducting nanowire single-photon detectors (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.

Current-voltage curves revealed that incorporating copper supports faster reset times, aligning with expectations of enhanced heat transfer away from the hotspot created when a photon is detected. Analysis using the Skocpol-Beasley-Tinkham (SBT) hotspot model quantified this improvement, showing approximately a 100-fold increase in the SBT slope parameter β and effective interfacial heat-transfer efficiency when compared to tantalum nitride (TaN) nanowires. The study involved fabricating TaN/Cu bilayer nanowires and characterising their superconducting properties.

A near-unity ratio of critical current to retrapping current was observed in these structures, further supporting the efficient heat removal facilitated by the copper layer. Measurements of 39nm thick TaN nanowires yielded a zero-temperature Ginzburg-Landau coherence length of 7nm and a critical temperature of 4.1 K, establishing baseline superconducting parameters. Process uniformity and scalability were also assessed across a 300mm wafer, indicating less than 5% variation in critical dimensions, room-temperature resistance, residual resistance ratio, critical temperature, and critical current across all measured linewidths. This consistency highlights the potential for wafer-scale fabrication of SNSPD arrays, crucial for applications demanding large detector areas. These findings demonstrate a trade-off between superconducting performance and heat-sinking efficiency in TaN/Cu bilayer nanowires, underscoring the viability of utilising wafer-scale fabrication techniques to produce fast, large-area SNSPD arrays suitable for photonic quantum computing, cosmological studies, and the development of neuromorphic computing devices.

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 300mm 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 100x increase in the Skocpol-Beasley-Tinkham (SBT) slope parameter beta 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 7nm and a critical temperature of 4.1 K for 39nm 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 300mm 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 areas such as photonic quantum computing, cosmology, and neuromorphic computing devices.

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 300mm 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 100times 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 superconducting nanowire single-photon detectors (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 beta 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 superconducting nanowire single-photon detectors (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 300mm silicon wafers utilising 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.