Semiconductor detectors of backscattered electrons in a scanning electron microscope: Characteristics and applications

A configuration of semiconductor detectors of backscattered electrons for a scanning electron microscope (SEM) is presented. The variable width of the detector rings and their oblique arrangement in the electron detection plane increases the detection efficiency by several times, thus making it possible to better separate the contrasts of surface-topography images and the studied-sample composition. By varying the accelerating voltage of the SEM and simultaneously choosing the appropriate detection angles of backscattered electrons, a sharper separation of layer-by-layer images of details of subsurface microstructures can be attained. It is shown that using a semiconductor detector and taking its response function (instrument function) into account, proximate assessments of the thicknesses of ultrathin nanometer-size film coatings on massive substrates can be performed.