Annual Report 2007 - The Australian Nanotechnology Network

made as optically perfect as possible using high-precision machining and a multipleelement
design that allows Figure 1: The scanning or microprobe configuration of a
helium atom microscope, analogous to the configuration of a scanning electron
microscope.
Figure 2: The imaging or microdetector configuration of a helium atom microscope,
analogous to the configuration of a standard optical microscope.
for electrostatic aberration correction. On a microscopic level the surface is etched flat
using a wet-etch technique that leaves the surface hydrogen-terminated and hence quite
resistant to contamination as well as having a good helium reflectivity (typically around
3%). Helium focusing from single-crystal silicon was demonstrated for the first time by
Allison and Holst [1] but a full characterization of the multiple-element, passivated silicon
mirror has yet to be done. The current configuration for the SHeM has a 5:1 distance ratio
between source-mirror and mirror-sample, hence a 50 micron skimmer will allow for a
spot size of 10 microns and a 2 micron skimmer giving a spot size of just 400nm, more
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