Fundamental and experimental aspects of diffraction for characterizing dislocations on bulk materials by electron channeling contrast imaging in scanning electron microscope
Abstract
In Scanning Electron Microscope (SEM), Electron Channeling Contrast Imaging (ECCI) is an attractive technique that allows direct observations of crystalline defects on bulk samples, thin films or substrates [1-4]. ECCI takes advantage from the strong dependence between the backscattred electrons intensity and the crystal orientation relative to the incident electron beam.
Defects, such as dislocations, can be imaged with a visibility of depth below the surface of about a hundred nanometers (the same order of magnitude of the thickness of a TEM thin foil or a thin layer deposited on a substrate). It has been shown that the channeling contrast generated by these linear defects is influenced by the modification of diffraction conditions caused by the lattice distortions around their core [5,6].
In this work, fundamental and experimental aspects of electron diffraction for characterizing dislocation by ECCI are reported. Interpretation of contrast in (g,-g) and its evolution along a Kikuchi band are given. Experimentally, the potentiality of the technique ECCI is explored on several dislocation configurations in grained Interstitial-Free (IF) steel (Fe − 1 %Si) where a dislocation dipole is observed and fully characterized for the first time in SEM [5].
References
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