Ion beam lithography using single ions

Presented here is a study to determine the conditions whereby holes etched along single ion tracks can be produced. Using standard tools of ion beam analysis a strategy has been developed to count single ions incident on a PMMA film spun onto a Si photodiode that functions as a detector. We investigate the sensitivity of PMMA to single ions as a function of the incident ion energy, mass and the PMMA development parameters. Non-contact atomic force microscopy (AFM) has been used to image the openings of holes etched along single ion tracks confirming the PMMA is sensitive to the passage of specific single ions. A high aspect ratio Si nanowhisker cantilever has been utilised to perform a quantitative analysis of the holes which are up to 45 run in diameter for 71 MeV Cu ions. (c) 2006 Elsevier B.V. All rights reserved.