Comparative study of image contrast in scanning electron microscope and helium ion microscope

Images of Ga+-implanted amorphous silicon layers in a 110 n-type silicon substrate have been collected by a range of detectors in a scanning electron microscope and a helium ion microscope. The effects of the implantation dose and imaging parameters (beam energy, dwell time, etc.) on the image contrast were investigated. We demonstrate a similar relationship for both the helium ion microscope Everhart-Thornley and scanning electron microscope Inlens detectors between the contrast of the images and the Ga+ density and imaging parameters. These results also show that dynamic charging effects have a significant impact on the quantification of the helium ion microscope and scanning electron microscope contrast. Lay description The helium ion microscope (HIM) is a recent development in the family of charged-particle microscopes and it operates on similar working principles to those of the conventional scanning electron microscope (SEM). We investigated the effects of imaging parameters on HIM and SEM images using a Ga+ focused ion beam implanted silicon sample. Our results highlight the similarity and difference between the two microscopes and also show that imaging parameters as well as specimen properties have a significant impact on the quantification of HIM and SEM metrology.