Ion transmission through nano-apertures

Abstract

Localisation of ion impacts with a resolution better than can be achieved with a focused ion beam microprobe may potentially be achieved by employing a high-aspect ratio nano-aperture mask. The present paper applies Monte Carlo methods to investigate the role of ion scattering and straggling through the aperture and the influence of these processes on the transmitted ion energy and intensity distribution. The objective of the investigation is to determine the potential of this method for delivering few or single ions to sub-100 nm locations on substrates. Simulation of 2 and 4 MeV He, 8 MeV F and 71 MeV Cu has indicated that the masking process is effective, with probabilities between 82% and 93% of obtaining single ions with full energy at the exit of the aperture. Possible applications include precision ion doping, single-ion machining and potentially ion beam analysis