In Helium Ion Microscopy a highly focused 30 KeV He+ ion beam interacts with the surface of a sample, causing a very localized emission of low energy secondary electrons. When the He+ beam is rastered across the surface of a sample, collecting the emitted secondary electrons generates an image with a lateral resolution of ~0.3 nm.

 

Contrary to Scanning Electron Microscopy (SEM) insulating samples do not need to be metal covered, and therefore finer details are not lost. In HIM, the accumulated positive charges at the surface of the sample during imaging can be mitigated using an electron flood source.

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HIM also possesses a superior depth perception in comparison to SEM, due to the particularly narrow solid angle of the He+ ions beam.

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Additionally, the He+ beam can be used to produce nanostructures, either by modifying a surface or by cutting through suspended structures.