Characterization of ion tracks in PMMA for single ion lithography
No Thumbnail Available
Date
2007-07
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The ultimate resolution in ion beam lithography (IBL) can be achieved by etching tracks modified by the passage of a single ion impact which has a diameter in the order of 10 nm. For precise counting of single ions, a Si photodiode is used as a substrate onto which a PMMA film is spun. We have macroscopically investigated the sensitivity of PMMA using 3 MeV H end found that a deposited energy density of greater than 1 eV/nm(3) is required to remove the PMMA film for 60 s developing in a water:IPA 1:4 solution. From this sensitivity measurement we have determined that 8 MeV F, 71 MeV Cu and 88 MeV I ions should produce enough damage in a single ion strike to create a hole etched along the latent damage track. We have used AFM imaging to quantitatively characterise the hole diameter as a function of the incident ion and the developing time. It was found that for up to 8 min development in a water:IPA solution holes were created for the F, Cu and I ions. SEM imaging has also been used to verify the holes seen by AFM imaging. © 2007, Elsevier Ltd.
Description
Keywords
Ions, PMMA, Ion beams, Resolution, Energy, Etching
Citation
Alves, A., Johnston, P. N., Reichart, P., Jamieson, D. N., & Siegele, R. (2007). Characterization of ion tracks in PMMA for single ion lithography. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 260(1), 431-436. doi:10.1016/j.nimb.2007.02.058