Highly 28Si enriched silicon by localised focused ion beam implantation

Title	Highly 28Si enriched silicon by localised focused ion beam implantation
Authors	Ravi Acharya, Maddison Coke, Mason Adshead, Kexue Li, Barat Achinuq, Rongsheng Cai, A. Baset Gholizadeh, Janet Jacobs, Jessica L. Boland, Sarah J. Haigh, Katie L. Moore, David N. Jamieson, Richard J. Curry
Magazine	Communications Materials
Date	05/07/2024
DOI	10.1038/s43246-024-00498-0
Introduction	Solid-state spin qubits in silicon crystals at milliKelvin temperatures are promising for scalable quantum computing. Naturally occurring silicon limits qubit coherence due to the 29Si isotope's nuclear spin. This study introduces a method to reduce 29Si in local silicon wafer regions using a 45 keV 28Si focused ion beam with high fluence. Analysis via nanoscale secondary ion mass spectrometry shows a significant reduction in 29Si concentration and comparable residual C and O levels to unimplanted wafers. Post-annealing, transmission electron microscopy confirms solid-phase epitaxial re-crystallisation of the amorphous enriched layer extending over 200 nm in depth.
Quote	Ravi Acharya, Maddison Coke and Mason Adshead et al. Highly 28Si enriched silicon by localised focused ion beam implantation. Commun Mater. 2024. Vol. 5(1). DOI: 10.1038/s43246-024-00498-0