Regensburg 2013 – scientific programme
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MI: Fachverband Mikrosonden
MI 7: Ion Beam Methods
MI 7.2: Talk
Wednesday, March 13, 2013, 11:30–11:45, H5
Broadening of a helium beam in hydrogen silsesquioxane — •Paul Alkemade1, Anja van Langen-Suurling1, Emile van Veldhoven2, and Diederik Maas2 — 1Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands — 2TNO Nano-instrumentation, TNO, Delft, The Netherlands
The realization of a practical helium gas field-ionization source made helium ion microscopy possible as an imaging and nanofabrication technique with high spatial resolution. Three key elements enable the high resolution: 1) the sub-nanometer probe size; 2) the fact that the emission of secondary electrons and backscattered ions is highly localized; and 3) the weak scattering of helium ions in matter.
With help of experiments and simulations we investigate how scattering of the penetrating ions causes broadening of the beam and thus loss of resolution. The helium beam energy is 30 keV and the material used is hydrogen silsesquioxane, a radiation sensitive material.
The results suggest that the most common simulation model (SRIM) underestimates the broadening of the penetrating helium beam. We will discuss causes of the observed discrepancy.