Collection of secondary electrons in scanning electron microscopes

Journal of Microscopy
I Müllerová, I Konvalina

Abstract

Collection of the secondary electrons in the scanning electron microscope was simulated and the results have been experimentally verified for two types of the objective lens and three detection systems. The aberration coefficients of both objective lenses as well as maximum axial magnetic fields in the specimen region are presented. Compared are a standard side-attached secondary electron detector, in which only weak electrostatic and nearly no magnetic field influence the signal trajectories in the specimen vicinity, and the side-attached (lower) and upper detectors in an immersion system with weak electrostatic but strong magnetic field penetrating towards the specimen. The collection efficiency was calculated for all three detection systems and several working distances. The ability of detectors to attract secondary electron trajectories for various initial azimuthal and polar angles was calculated, too. According to expectations, the lower detector of an immersion system collects no secondary electrons I and II emitted from the specimen and only backscattered electrons and secondary electrons III form the final image. The upper detector of the immersion system exhibits nearly 100% collection efficiency decreasing, however, ...Continue Reading

References

Jul 13, 2002·Journal of Electron Microscopy·Akira YonezawaBjörn Wannberg
Aug 27, 2005·Journal of Electron Microscopy·Ludek Frank
Oct 27, 2006·Scanning·Ivo Konvalina, Ilona Müllerová
Feb 7, 2009·Journal of Microscopy·L Novák, I Müllerová

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