A new atomic layer deposition technique will grow ultra-thin films of niobium nitride to replace the aluminium that currently limits the performance of quantum computer chips. Today’s superconducting qubits—the basic units of quantum computers—suffer from energy loss and inconsistent behaviour because aluminium films oxidise and lack uniformity. This project swaps aluminium for niobium nitride, a material that superconducts at higher temperatures and resists oxidation. The team will use atomic layer deposition to grow these films with atomic-scale precision, then build Josephson junctions (the switching elements inside qubits) and coat high-aspect-ratio through-silicon vias to create 3D interconnects between stacked processor layers. If the films and junctions match or beat conventional qubit performance, the work could remove a key bottleneck in scaling quantum processors from dozens to thousands of qubits. That would accelerate practical quantum computing for drug discovery, energy grid optimisation, and artificial intelligence. The project also benefits industrial partners Oxford Instruments Plasma Technology and Kelvin Nanotechnology by improving their fabrication capabilities for sensing and communications. The research is applied materials science with a clear engineering target; it does not explore fundamental quantum phenomena but instead solves a manufacturing problem that currently blocks progress.
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Context and Challenge This project focuses on developing and analyzing advanced materials for superconducting and quantum technologies, specifically targeting the improvement of superconducting qubits, which are essential for quantum computing. Traditional materials used in qubits, like aluminum, face limitations such as high dielectric loss and poor uniformity, which negatively impact qubit performance and scalability. To address these issues, we propose using niobium nitride (NbN), which offers higher critical temperature and reduced oxidation, potentially enhancing qubit stability and performance. These advancements are crucial as quantum computing revolutionises various fields including drug discovery, energy management, artificial intelligence, and autonomous systems. Aims and Objectives Advanced Material Fabrication Utilize state-of-the-art atomic layer deposition (ALD) to grow high-uniformity NbN layers. Develop high-quality NbN/AlN/NbN Josephson Junctions (JJs) with precise control over the tunnel barriers. Comprehensive Characterization Conduct thorough material characterization using advanced tools such as electron microscopy and atomic force microscopy (AFM) at both room temperature and cryogenic conditions. Investigate the material properties of these films, focusing on their stoichiometry, critical temperature, and kinetic inductance. 3D Integration Develop high-aspect ratio through-silicon vias (TSVs) coated with nitride films to enable 3D superconducting interconnects, facilitating large-scale quantum processor integration. Fabricate and connect superconducting qubits, interposer chips, and routing chips to create integrated 3D quantum circuits. Performance Optimization Benchmark ALD-grown NbN films and JJs against conventional qubit technologies. Optimize fabrication processes to minimize defects and enhance qubit coherence times. Potential Applications and Benefits The successful development of these advanced superconducting materials and structures will have significant implications for quantum technology. By improving the performance and scalability of superconducting qubits, this project will contribute to the advancement of quantum computing. Quantum computing has the potential to revolutionize fields such as drug discovery, where it can drastically reduce the time required to develop new medications, and energy management, where it can optimize the distribution and usage of energy resources for better sustainability. Moreover, the project's outcomes will benefit industrial partners like Oxford Instruments Plasma Technology (OIPT) and Kelvin Nanotechnology (KNT), enhancing their technologies and opening new market opportunities through innovations in areas such as sensing, communications, and fundamental research. Broader Impact This project aligns with national and global priorities in quantum technology development, supporting the UK's strategic vision to become a leading science and technology superpower. The work will be disseminated widely through high-impact journal publications, conferences, and public engagement, ensuring broad visibility and impact. Presentations at international conferences, such as the APS March Meeting and IEEE Quantum, will further enhance the project's visibility within the scientific community. This project promises robust and reliable outcomes through collaboration with leading institutions and leveraging existing infrastructure, such as the James Watt Nanofabrication Centre at the University of Glasgow and the advanced facilities at the University of Tokyo. The integration of industrial-grade processes and advanced material research positions this project to pioneer significant advancements in the field of quantum computing, driving both scientific and economic benefits. Ultimately, the project reduces barriers to entry for developing superconducting technologies, paving the way for the commercialization of high-quality quantum devices and supporting the growth of the quantum technology industry. By addressing fundamental issues with superconducting qubits and improving their stability and lifespan, this project aims to make quantum computing more viable and scalable for industrial applications, with a profound impact on the future of technology and society.
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