A novel technique for visualizing electron beam induced charging

Charging is one of the most important problems encountered in scanning electron microscopy and as a result this phenomenon it has received a lot of both theoretical and experimental attention. Despite this, many questions remain about the nature and behavior of charging because of the limitations of the experimental techniques available to study it. For example, although it is now straightforward to determine in situ the surface potential of a sample that is charging during irradiation, it is difficult to measure the lateral extent of the charging, or its persistence once the incident beam is switched off. We describe here a simple technique which provides a rapid way of visualizing the temporal and spatial behavior of charging phenomena.