The identification of crystallographic phases in the scanning electron microscope (SEM) has been limited by the lack of a simple way to obtain electron diffraction data of an unknown while observing the microstructure of the specimen. With the development of charge coupled device (CCD)-based detectors, backscattered electron Kikuchi patterns, alternately referred to as electron backscattered diffraction (EBSD) patterns, can be easily collected. Previously, EBSD has been limited to crystallographic orientation studies due to the poor pattern quality collected with video rate detector systems. With CCD detectors, a typical EBSD can now be acquired from a micron or submicron sized crystal using an exposure time of 1–10 s with an accelerating voltage of 10–40 kV and a beam current as low as 0.1 nA. Crystallographic phase analysis using EBSD is unique in that the properly equipped SEM permits high magnification images, EBSDs, and elemental information to be collected from bulk specimens. EBSD in the SEM has numerous advantages over other electron beam-based crystallographic techniques. The large angular view (∼70°) provided by EBSD and the ease of specimen preparation are distinct advantages of the technique. No sample preparation beyond what is commonly used for SEM specimens is required for EBSD.
Use of backscattered electron detector arrays for forming backscattered electron images in the scanning electron microscope
