Methods of topography mode realization in scanning electron microscope

In the paper the analog and digital methods of TOPO mode realization in a scanning electron microscope (SEM) by means of backscattered electron signal (BSE) have been presented. The detector system consists of four BSE detectors, their biases, and the same number of current sensitive preamplifiers placed inside the vacuum chamber. Two pairs of opposing semiconductor diodes of a small surface placed mutually perpendicularly have been used. BSE signals enter low pass filters and the next amplification stages in the signal conditioning circuit in order to prepare them for further processing.