Intense micro-ion beams from electromagnetic wave generated plasmas: high aspect ratio structuring, capillary self-focusing and enhanced nonlinear demagnification below the Debye length

Plasma based micro-nano ion beams have emerged as a useful tool in many research applications such as patterning, rapid fabrication, modification of surface properties, including fundamental research in optics and field emission of created nanostructures. The advantage of obtaining higher currents and variable projectile masses by employing different gaseous plasma ions in a newly developed system in our laboratory, have significantly expanded the applicability beyond conventional FIB systems. High aspect ratio microstructures (~100-1000) have been created employing 26 keV Ar, Kr and Ne ion beams, and the structuring capability have been evaluated with a new parameter – current normalized force. Capillary guiding of these beams has demonstrated self focusing whereby the beam size can be further reduced and guided. The effect of plasma and beam parameters on focal dimensions have revealed a unique feature of enhanced nonlinear demagnification when the plasma electrode aperture is reduced to below the Debye length. (author)