Went M R, Winkelmann A, Vos M
Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT, Australia.
Ultramicroscopy. 2009 Sep;109(10):1211-6. doi: 10.1016/j.ultramic.2009.05.004. Epub 2009 May 14.
Diffraction patterns of backscattered electrons can provide important crystallographic information with high spatial resolution. Recently, the dynamical theory of electron diffraction was applied to reproduce in great detail backscattering patterns observed in the scanning electron microscope (SEM). However, a fully quantitative comparison of theory and experiment requires angle-resolved measurements of the intensity and the energy of the backscattered electrons, which is difficult to realize in an SEM. This paper determines diffraction patterns of backscattered electrons using an electrostatic analyzer, operating at energies up to 40 keV with sub-eV energy resolution. Measurements are done for different measurement geometries and incoming energies. Generally a good agreement is found between theory and experiment. This spectrometer also allows us to test the influence of the energy loss of the detected electron on the backscattered electron diffraction pattern. It is found that the amplitude of the intensity variation decreases only slowly with increasing energy loss from 0 to 60 eV.
背散射电子的衍射图案能够以高空间分辨率提供重要的晶体学信息。最近，电子衍射的动力学理论被用于详细再现扫描电子显微镜（SEM）中观察到的背散射图案。然而，要对理论和实验进行完全定量的比较，需要对背散射电子的强度和能量进行角度分辨测量，而这在扫描电子显微镜中很难实现。本文使用静电分析仪确定背散射电子的衍射图案，该分析仪在高达40keV的能量下运行，能量分辨率可达亚电子伏特。针对不同的测量几何结构和入射能量进行了测量。理论与实验结果总体吻合良好。该光谱仪还使我们能够测试检测到的电子能量损失对背散射电子衍射图案的影响。结果发现，随着能量损失从0增加到60eV，强度变化的幅度仅缓慢减小。
