Image simulation in scanning electron microscopy
Image simulation, as a means of image interpretation, has been an important component of high resolution transmission electron microscopy for many years. By contrast scanning electron microscopists have relied almost exclusively on simple visual analogies to understand the micrographs that they produce. However with the development of SEMs capable of near atomic levels of resolution, and with the requirement for accurate dimensional metrology of sub-micron features in semiconductor devices using the SEM, a more quantitative approach to image formation and analysis is needed.Image simulation in the SEM encounters several special problems. Firstly, the signal displayed to form the micrograph is not well defined in terms of either the contrast mechanisms which give rise to it, or the energy and origin of the electrons actually collected to produce the signal.