Focused Ion Beam - Helium Ion Microscope (HeIM)

Helium Ion Microscope (HeIM)

Another ion source seen in commercially available instruments is a helium ion source, which is inherently less damaging to the sample than Ga ions although it will still sputter small amounts of material especially at high magnifications and long scan times. As helium ions can be focused into a small probe size and provide a much smaller sample interaction than high energy (>1 kV) electrons in the SEM, the He ion microscope can generate equal or higher resolution images with good material contrast and a higher depth of focus. Commercial instruments are capable of sub 1 nm resolution.