Applied Physics Seminar

Abstract:

Modern CMOS integrated circuits represent the pinnacle of current human technological achievement, in which tens of billions of transistors with feature sizes around 20 nm are integrated onto a single chip. The promise of quantum technologies has stimulated research into a diverse range of physical technology platforms, including superconducting circuits and atomic arrays. Nevertheless, realising quantum technologies such as quantum computers within modern ICs is attractive due to the potential for accelerated scaling and integration with digital and analogue electronics.

Modern CMOS ICs such as Global Foundries 22FDX already support superconducting thin film materials (e.g. TiN) with the gate stack. We find that these films exhibit high kinetic inductance (1 nH/square), enabling the creation of super-inductors natively within the CMOS process [1]. By integrating these superinductors on-chip with radio frequency single electron transistors (rfSETs) used for charge sensing, we show a sensitivity increase of over two orders of magnitude over state-of-the-art, combined with a area reduction of 10,000 compared to off-chip inductors. We show how arrays of 1,024 quantum dots can be addressed on-chip using RF multiplexing [2]. By tuning such quantum dots to single electron occupation and employing a nearby charge sensor we demonstrate read-out of a single electron spin with this CMOS technology node. Beyond providing the basis for dense arrays of integrated and high-performance qubit sensors, the realization of high-kinetic-inductance superconducting devices integrated within modern silicon ICs opens many opportunities, including kinetic-inductance detector arrays for astronomy and the study of metamaterials and quantum simulators based on 1D and 2D resonator arrays [3].

Illustrating the future potential for scaling qubit arrays based on this technology, we present a prototype 4-qubit processor manufactured using another silicon MOS platform, still using 300mm wafer processing. This quantum processing unit was integrated within a full-stack system and delivered to the UK's National Quantum Computer Centre.

[1] TH Swift et al., arXiv:2507.13202 (2025)

[2] EJ Thomas, VN Ciriano-Tejel et al., Nature Electronics 8, 75 (2025)

[3] X Zhang, E. Kim et al., Science 379, 278 (2023)

More about the Speaker:

John Morton is Professor of Nanoelectronics & Nanophotonics at University College London (UCL) with research interests in spin-based quantum technologies such as quantum computers and quantum sensors, in a range of materials and devices. After reading Electrical Engineering at University of Cambridge, John undertook at PhD at University of Oxford, to work on techniques for controlling spins as quantum bits. John was a Royal Society University Research Fellowship from 2008-16, and he has held back-to-back European Research Commission (ERC) grants. In 2012 he moved from Oxford to UCL where he is Director of UCL's Quantum Science and Technology Institute and since 2025, PI of the UK's Research Hub on Quantum Biomedical Sensors (Q-BIOMED). John is a co-founder of two successful quantum computing companies: Quantum Motion (developing silicon-based quantum computing hardware) and Phasecraft (developing quantum algorithms) which together employ over 100 researchers in quantum technology. John's awards include the Nicholas Kurti European Science prize (2008), the Institute of Physics Moseley Medal (2013) in experimental physics, and the Sackler International Prize in Physical Sciences (2016). John has published over 150 papers with 15,000 citations and has an h-index of 57. John is active in the public engagement of science, including public exhibitions, documentaries, videos, radio broadcasts and popular articles on quantum science and technology.