Add-on lens attachments for the scanning electron microscope

Abstract

This article summarized recent work carried out on add-on lens attachments for the SEM. It described how add-on lenses can be used to improve the resolution of conventional SEMs by a factor of 3 or more. Add-on lenses do not require any fundamental change to the SEM's normal mode of operation and are mounted conveniently onto the specimen stage. Theoretical and experimental work was presented to illustrate how add-on lenses can be used to lower the landing energy of the primary beam at the specimen in a conventional SEM. Research work demonstrating how add-on lenses can transform a conventional SEM into a flexible analytical tool capable of acquiring the secondary electron energy spectrum was reported. By obtaining this kind of information, a conventional SEM can operate in a quatitative voltage contrast or material contrast mode, providing voltage or compositional information on the nanoscale range. Last, it was shown how the add-on lens concept provides a simple and convenient platform for testing novel objective lens ideas. © 2002 Elsevier B.V. All rights reserved.