Abstract: | Focused ion beams (FIB) are widely used for research and applications in nanoscience and technology. We have developed a compact
microwave plasma based multi element FIB (MEFIB) system in order to widen the applications and overcome the limitations faced
by conventional Liquid Metal Ion Source (LMIS) based FIB systems, that provide primarily Ga ions. The MEFIB source provides
high density plasmas (∼1.5 × 1011 cm−3) in a compact cross section. Recently the ion energy spread in the plasma meniscus from where the beams are extracted is
found to be small (∼5 eV) 1–3]. The beam extraction and focusing are carried out using electrostatic multi electrode assembly.
AXCEL INP and SIMION simulation codes are employed for the design of electrostatic Einzel lenses for beam focusing. The beam
focal point is measured using a specially designed three slit Faraday cup and the spot size is measured by the micrography
of craters formed by the focused ion beams impinging on copper and aluminium substrates. The initial experimental results
show a focused beam spot size of ∼ 25 micron which is in good agreement with the simulations. By further reduction of electrode
apertures and operating the second Einzel lens at higher potentials, submicron focused ion beams can be expected. |