Microwave-Powered Plasma Ion Sources for Multi-Elemental Focused Ion Beam Systems

What is it about?

Researchers have developed a compact microwave-driven plasma ion source for focused ion beam applications, experimenting with various gas species such as argon, krypton, and hydrogen. The octupole multicusp configuration showed better performance in terms of plasma density and electron temperature. The ion source is capable of producing multielemental focused ion beams for nanostructuring and implantations. The initial simulation results for the focused beams have been presented. The microwave-driven subcutoff plasma ion source has been optimized for multielemental FIB applications. The plasma source's performance was compared between octupole and hexapole configurations, with the octupole configuration showing better results. Ion current density measurements were obtained for three different gas species and various plasma electrode apertures, with an observed ion current density of up to 2 A/cm² for a 1 mm PE aperture. The AXCEL-INP code was used to simulate the ion beam with electrostatic Einzel lenses, resulting in a 10 m beam spot size. The high brightness source promises potential for FIB systems. Existing liquid metal ion source (LMIS) based FIB systems can only provide gallium ions, limiting their functionality and applicability in areas requiring FIBs of other elements. The development of reliable, stable, and alternative plasma-based ion sources for multielemental FIBs opens up new possibilities for research and development in nanotechnology.

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Why is it important?

The development of an alternative, reliable, and stable microwave-driven plasma ion source for producing multielemental focused ion beams (FIBs) is important because it expands the applicability and functionality of FIB systems in various fields such as nanotechnology, material research, and biological studies. Commercial liquid metal ion sources currently limit FIB systems to only gallium ions, while a versatile plasma ion source would enable the use of FIBs with other elements, opening up new possibilities for research and development of nanodevices. Key Takeaways: 1. The microwave-driven subcutoff plasma ion source has been optimized for multielemental FIB applications. 2. The octupole configuration shows superior performance in terms of plasma density and electron temperature compared to the hexapole configuration. 3. Ion current densities ranging from a few hundreds to over 1000 mA/cm² have been obtained with different plasma electrode apertures. 4. AXCEL-INP code is used to simulate the ion beam with electrostatic Einzel lenses, and a ≤10 μm beam spot size is obtained with the input parameters taken from the experimental data. 5. The high brightness source promises potential for FIB systems, enabling research and development of nanodevices with various elemental FIBs.