Direct evaluation of threading dislocations in 4H-SiC through large-angle convergent beam electron diffraction
Direct evaluation of threading dislocations in 4H-SiC through large-angle convergent beam electron diffraction
复制标题
通过大角度会聚束电子衍射直接评估 4H-SiC 中的穿透位错
DOI：
10.1080/14786435.2019.1673497
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发表时间：
2020
影响因子：
1.6
通讯作者：
H. Tsuchida
中科院分区：
文献类型：
--
作者：
J. P. Hadorn;R. Tanuma;I. Kamata;H. Tsuchida
摘要在这项研究中，在4 H-SiC外延层的螺纹位错（TD）的结构直接使用大角度会聚束电子衍射（LACBED）通过透射电子显微镜（TEM），通过检查由于位错线的存在下的反射分裂的特点。以前，X射线形貌（XRT）映射结合射线追踪模拟已被证明是一种有效的方法，用于成像和区分常见的TD类型和变种的4 H-SiC。在这项工作中，基于XRT的结果的有效性进行了验证LACBED通过直接评估和区分的Burgers矢量和物理晶体学特征的所有螺纹边缘，螺纹螺钉，螺纹混合位错变体。LACBED结果与基于XRT的TD类型和变体结果一致。螺旋或半平面取向和Burgers矢量确定LACBED分析每个TD是自洽的。对于-TEDs的情况下，原子分辨率的核心结构的分析，通过高角度环形暗场扫描TEM，直接揭示了两个半平面，每个具有伯格斯矢量分量，这些分量的总和被确认为。最后，讨论了一种高效的4 H-SiC中TD的LACBED分析算法。
ABSTRACT In this study, the structures of threading dislocations (TDs) in a 4H-SiC epilayer were directly characterised using large-angle convergent beam electron diffraction (LACBED) via transmission electron microscopy (TEM), by examining the splitting of reflections due to the presence of dislocation lines. Previously, X-ray topography (XRT) mapping in combination with ray-tracing simulations has been shown to be an efficient method for imaging and differentiating common TD types and variants in 4H-SiC. In this work, the validity of XRT-based results was verified by LACBED through direct evaluation and differentiation of the Burgers vectors and physical crystallographic features of all threading edge, threading screw, and threading mixed dislocations variants. The LACBED results agreed with the XRT-based results with respect to TD type and variant. The screw-sense or half-plane orientation and Burgers vector determined from LACBED analysis for each TD were self-consistent. For the case of -TEDs, atomic-resolution analysis of the core structure, through high-angle annular dark field scanning TEM, directly revealed two half-planes, each with a Burgers vector component, and the sum of these components was confirmed to be . Finally, an algorithm for efficient LACBED analysis of TDs in 4H-SiC was discussed.