6533b853fe1ef96bd12ac047

RESEARCH PRODUCT

Aperture-edge scattering in MeV ion-beam lithography. I. Scattering from a straight Ta aperture edge

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Collimators are widely used to define MeV ion beams. Recent studies have shown the capability of collimators to define beams of MeV ions with sub-100nm dimensions. Such nanometer beams have potential applications in MeV ion-beam lithography, which is the only maskless technique capable of producing extremely high aspect-ratio micro- and nanostructrures, as well as in high-resolution MeV ion-beam-based tomography. The ion scattering from the collimator edges that define the beam can be a resolution-restricting factor in these applications. Scattering processes at edges are difficult to study using conventional simulation codes because of the complicated geometry. In this part of the work, the authors used the GEANT4 toolkit as a simulation tool for studying the behavior of ions impinging onto, or in close proximity to, a single straight aperture edge. Results from simulations are presented for realistic beams of 3MeV He ions with 0.2–1mrad divergence incident on a 100-μm-thick Ta plate. The contribution fr...