Dresden 2017 – wissenschaftliches Programm
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MI: Fachverband Mikrosonden
MI 1: Analytical Electron Microscopy: SEM and TEM-based Material Analysis
MI 1.1: Hauptvortrag
Montag, 20. März 2017, 10:00–10:30, MER 02
Point-group sensitive interpretation of EBSD patterns, and the impact of channeling-in and channeling-out of electrons — •Gert Nolze1 and Aimo Winkelmann2 — 1Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany — 2Bruker Nano GmbH, Am Studio 2D, 12489 Berlin, Germany
Recent studies contradict the common belief that electron backscatter diffraction follows Friedel’s rule. The presentation will demonstrate that entire orientation maps collected under standard acquisition conditions can be processed by pattern matching of experimental with simulated patterns which enables to distinguish between (hkl) and (hkl). However, the polarity determination for phases such as GaAs is very difficult since Ga an As have a similar contribution to the backscattered intensity of hkl and hkl. We will show that in such case the energy-dispersive X-ray signal can be used, but presently for single orientations only.
It is also frequent practice that an EBSD pattern is mainly reduced to its backscattered diffraction part. This also called channeling-out signal is used for the orientation interpretation, phase interpretation etc. The presentation will prove that the channeling-in of the electron beam reacts clearly more sensitive regarding orientation variations and is responsible for the orientation contrast in images e.g. collected by a backscattered electron detector. Despite the fascinating misorientation sensitivity a quantitative evaluation seems to be very unlikely.