Idealized spatial emission distribution of secondary electrons

Abstract

The spatial distribution of secondary electrons generated by a primary electron beam incident at a point of the sample surface is calculated for samples of varying thicknesses. The current density generated under these conditions is also calculated for several different angles of incidence. According to the calculations, which are based on a commonly used idealized model, most secondary electrons leave the sample within a mean free path of their point of excitation, which is 10–20 Å for metals. Because thin metal coatings are used to prevent many insulating samples from charging, these results relate to the ultimate resolution that one can expect in secondary emission scanning electron microscopy.