A one-dimensional model is proposed for analysing static capacitance contrast (SCC) in scanning electron microscopy. For the large-scale integrated specimen covered by an insulating thin film, the imaging signal is calculated considering the redistribution of secondary electrons (SEs) and the charging process of the equivalent effective capacitance between the irradiation point and substrate. The calculated SCC as a function of the irradiation charge density is in good agreement with the experimental SCC. It is confirmed that the SCC arises from the redistribution of SEs and the difference in the effective capacitance of irradiation points under the condition of positive charging.
A homogenized surface potential is desirable for the observation of a pre-irradiated insulating specimen using a scanning electron microscope because the residual surface potential may affect the imaging properties of the specimen. To homogenize the residual surface potential, the specimen should be subjected to the irradiation of an electron beam with the total electron yield greater than one. The expression of the equilibrium potential is derived based on the charge balance condition in the equilibrium state and the potential value is found to increase mainly with the secondary electron (SE) yield and the most probable emission energy of SEs. Further numerical calculations of SE trajectories show that affected by different surface potentials, SEs leave or return to the specimen surface to change the net charge flux into the specimen. This thereby increases the surface potential below the equilibrium potential and decreases that above the equilibrium potential, homogenizing the surface potential.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.