SuperFab, located at Royal Holloway, University of London, is the UK’s national facility for the development of superconducting quantum technology with a focus on quantum computing. Although a relatively new facility it has already become central to the UK’s efforts to become a world-leader in quantum technology and commercialise quantum computing. NPL is working with the SuperFab team to establish best practice for characterising superconducting quantum devices.
SuperFab has state-of-the equipment for device fabrcication, including thin-film deposition and e-beam lithography. However, there is a crucial bottleneck when developing state-of-the-art fabrication processes. The need to characterise many devices in order to gather data about parameter spread and device variability can be extremely time-consuming and resource intensive. There is also a requirement for calibrated measurements which allow for verification and comparison of different design, which can be difficult to achieve once a device is fully packaged. The is especially important for RF/microwave circuits such as superconducting quantum processors.
Our team has therefore procured and commissioned a new cryogenic probe station for automated on-wafer testing of superconducting circuits, which is has been installed at Royal Holloway. This will allow users to automatically, and with good repeatability, test many on-wafer devices at temperatures down to 4K. It can also be used for on-wafer testing of RF structures and components at frequencies up to 18 GHz.
Using these new capabilities and learnings, we have developed an improved process for the design, modelling and fabrication of multi-qubit quantum circuits. This is feeding into a roadmap for fabrication of multi-qubit circuits research and benchmarking. The ultimate goal is to support the fledgling industry and academic community with benchmarking and metrology.
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