Speaker
Description
Advances in focused ion beam (FIB) sources are key to expand the analytical capabilities of secondary ion mass spectrometers (SIMS) while driving down their operational costs, enabling new science in fields ranging from geology, biology, medicine to space sciences [1].
A novel dual-polarity ion source is being developed to equip SIMS with a high-performance, reliable and affordable alternative to existing state-of-the-art sources [2]. The source leverages a novel combination of features to deliver a brightness equivalent to or greater than state-of-the-art negative oxygen ion sources.
The radio-frequency (RF) birdcage resonant antenna favours an efficient inductive plasma generation while minimising the capacitive coupling and associated energy spread [3,4]. A differential bias sheath control scheme enables the production of high-current density negative ion beams from low-power density plasmas. These two key features result in a source design with relaxed constraints regarding thermal and high-voltages management, allowing water to be used as the cooling fluid rather than perfluoropolyethers.
The source performances are characterised by a suite of dedicated diagnostics (Faraday cup, Wien filter, retarding field analyser and scintillators) as well as through test campaigns on Cameca IMS-1280 and NanoSIMS 50L SIMS. With this work focusing on negative oxygen ion beam generation, initial results show a source-side total negative ion beam current density up to 10.7$\,\rm mA/cm^2$ consisting approximately of 63$\%$ O$^-$, 25$\%$ O$_2^-$ and 12$\%$ O$_3^-$. An O$^-$ ion probe of current density $\sim 113 \,\rm mA/cm^2$ with a stability better than 1$\rm \%/h$ and 5$\rm \%/24h$ has been observed on the IMS-1280. First test on the NanoSIMS delivered images of resolution equivalent to state-of-the-art O$^-$ sources.
| Email address | felicien.filleul@epfl.ch |
|---|---|
| Visitor's Visa | yes |
| Classification | Other negative ion sources for fusion, accelerators, and other applications |
| Footnote | [1] K. Höflich, G. Hobler, F. I. Allen, T. Wirtz, G. Rius, L. McElwee-White, A. V. Krasheninnikov, M. Schmidt, I. Utke, N. Klingner et al., “Roadmap for focused ion beam technologies,” Applied Physics Reviews, vol. 10, no. 4, 2023. [2] F. Filleul, P. Guittienne, F. Furno, J. Marin Carbonne, A. Meibom, and F. Plane, “Resonant antenna ion source,” EP26174302.5, 2026-04-23. [3] P. Guittienne, S. Lecoultre, P. Fayet, J. Larrieu, A. Howling, and C. Hollenstein, “Resonant planar antenna as an inductive plasma source,” Journal of Applied Physics, vol. 111, no. 8, 2012. [4] P. Guittienne, A. Howling, and F. Furno, Resonant Network Antennas for Radio-Frequency Plasma Sources: Theory, technology and applications. IOP Publishing, 2024. |