Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.
J Microsc. 2011 Dec;244(3):311-9. doi: 10.1111/j.1365-2818.2011.03538.x. Epub 2011 Aug 25.
Electron channelling contrast imaging of threading dislocations in GaN (0002) substrates and epitaxial films has been demonstrated using a conventional polepiece-mounted backscatter detector in a commercial scanning electron microscope. The influence of accelerating voltage and diffraction vector on contrast features denoting specific threading dislocation types has been studied. As confirmed by coordinated transmission electron microscopy analysis, electron channelling contrast imaging contrast features for edge-type threading dislocations are spatially smaller than mixed-type threading dislocations in GaN. This ability to delineate GaN edge threading dislocations from mixed type was also confirmed by defect-selective etch processing using molten MgO/KOH. This study validates electron channelling contrast imaging as a nondestructive and widely accessible method for spatially mapping and identifying dislocations in GaN with wider applicability for other single-crystal materials.
利用商业扫描电子显微镜中的传统极靴安装背散射探测器，已经证明了在 GaN（0002）衬底和外延膜中螺位错的电子通道对比成像。研究了加速电压和衍射矢量对表示特定螺位错类型的对比特征的影响。通过协调的透射电子显微镜分析证实，GaN 中边缘型螺位错的电子通道对比成像对比度特征在空间上小于混合型螺位错。通过使用熔融 MgO/KOH 进行缺陷选择性腐蚀处理，也证实了从混合类型中描绘 GaN 边缘螺位错的能力。这项研究验证了电子通道对比成像作为一种非破坏性的、广泛适用的方法，用于对 GaN 中的位错进行空间映射和识别，并且对其他单晶材料具有更广泛的适用性。
