2021 Volume 64 Issue 9 Pages 424-429
Helium ion microscopy (HIM) is similar to scanning electron microscopy (SEM), which uses a helium ion beam instead of an electron beam. The contrast of HIM secondary electron images, HIM backscattered ion images, and SEM images are not identical because the incident and signal particles are different.
In this paper, the images measured in 2020 were compared with those measured in 2012 under the same conditions, and the reason of the differences of some elements due to aging were discussed. Surface oxidation affected the change for the eight years. However, the change was not as simple as the highly oxidizable elements changing significantly. This indicates that whether changes are observed or not depends on the combination of the thickness of the oxide layer and the mean free path of the signal particles.
