SEM Images Obtained with an Energy and Takeoff Angle Selective Detector

Abstract

SEMs are usually equipped with a backscattered electron detector and a secondary electron detector. In addition to these, alternative detectors have recently been employed to obtain images with additional information content. These detectors are designed to detect electrons emitted within a certain predefined range of energy and takeoff angle. However, no attempt has ever been made to design a detector that allows direct detection of electrons in a user-defined energy and takeoff angle range. In this study, an electron detector was designed and experimentally manufactured to detect electrons emitted in a defined, variable range of energy and takeoff angle. With this “E-θ detector” a set of images was taken to obtain electrons in two distinct ranges of energy and two distinct ranges of takeoff angle. These images were compared with those obtained by ordinary secondary and backscattered electron detectors. As an application example, clear contrast originating from crystal orientation of a spherical tungsten single crystal was observed in an image composed of high takeoff angle secondary electrons. [DOI: 10.1380/ejssnt.2014.279]