Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle (Saale), Germany.
Ultramicroscopy. 2010 Feb;110(3):190-4. doi: 10.1016/j.ultramic.2009.11.008. Epub 2009 Nov 24.
We analyze the contrast reversal of Kikuchi bands that can be seen in electron backscatter diffraction (EBSD) patterns under specific experimental conditions. The observed effect can be reproduced using dynamical electron diffraction calculations. Two crucial contributions are identified to be at work: First, the incident beam creates a depth distribution of incoherently backscattered electrons which depends on the incidence angle of the beam. Second, the localized inelastic scattering in the outgoing path leads to pronounced anomalous absorption effects for electrons at grazing emission angles, as these electrons have to go through the largest amount of material. We use simple model depth distributions to account for the incident beam effect, and we assume an exit angle dependent effective crystal thickness in the dynamical electron diffraction calculations. Very good agreement is obtained with experimental observations for silicon at 20keV primary beam energy.
我们分析了在特定实验条件下电子背散射衍射（EBSD）图谱中可见的菊池带反衬度反转。通过动态电子衍射计算可以再现观察到的效应。确定有两个关键的贡献在起作用：首先，入射束在深度上产生非相干背散射电子的分布，这取决于束的入射角。其次，在出射路径中的局域非弹性散射导致掠出射角的电子出现明显的反常吸收效应，因为这些电子必须穿过最多的材料。我们使用简单的模型深度分布来解释入射束的影响，并在动态电子衍射计算中假设出射角相关的有效晶体厚度。对于 20keV 初级束能量的硅，实验观察与计算结果非常吻合。
