Understanding defects and their roles in plastic deformation and device reliability is important for the development of a wide range of novel materials for the next generation of electronic and optoelectronic devices. We introduce the use of gaseous secondary electron detectors in a variable pressure scanning electron microscope for non-destructive imaging of extended defects using electron channelling contrast imaging. We demonstrate that all scattered electrons, including the secondary electrons, can provide diffraction contrast as long as the sample is positioned appropriately with respect to the incident electron beam. Extracting diffraction information through monitoring the modulation of the intensity of secondary electrons as a result of diffraction of the incident electron beam, opens up the possibility of performing low energy electron channelling contrast imaging to characterise low atomic weight and ultra-thin film materials. Our methodology can be adopted for large area, nanoscale structural characterisation of a wide range of crystalline materials including metals and semiconductors, and we illustrate this using the examples of aluminium nitride and gallium nitride. The capability of performing electron channelling contrast imaging, using the variable pressure mode, extends the application of this technique to insulators, which usually require conducting coatings on the sample surface for traditional scanning electron microscope based microstructural characterisation.

中文翻译：

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通过扫描电子显微镜中初级电子衍射产生的次级电子强度变化测量晶体缺陷

了解缺陷及其在塑性变形和器件可靠性中的作用对于为下一代电子和光电器件开发各种新型材料非常重要。我们介绍了在可变压力扫描电子显微镜中使用气态二次电子探测器，使用电子通道对比成像对扩展缺陷进行非破坏性成像。我们证明，只要样品相对于入射电子束的位置适当，所有散射电子，包括二次电子，都可以提供衍射对比度。通过监测由入射电子束衍射引起的二次电子强度调制来提取衍射信息，开辟了执行低能电子通道对比成像以表征低原子量和超薄膜材料的可能性。我们的方法可用于包括金属和半导体在内的各种晶体材料的大面积纳米级结构表征，我们使用氮化铝和氮化镓的例子来说明这一点。使用可变压力模式执行电子通道对比成像的能力，将该技术的应用扩展到绝缘体，通常需要在样品表面进行导电涂层，以进行基于传统扫描电子显微镜的微观结构表征。包括金属和半导体在内的各种晶体材料的纳米级结构表征，我们使用氮化铝和氮化镓的例子来说明这一点。使用可变压力模式执行电子通道对比成像的能力将这种技术的应用扩展到绝缘体，通常需要在样品表面进行导电涂层，以进行基于传统扫描电子显微镜的微观结构表征。包括金属和半导体在内的各种晶体材料的纳米级结构表征，我们使用氮化铝和氮化镓的例子来说明这一点。使用可变压力模式执行电子通道对比成像的能力，将该技术的应用扩展到绝缘体，通常需要在样品表面进行导电涂层，以进行基于传统扫描电子显微镜的微观结构表征。