Dictionary Indexing of Electron Channeling Patterns
Dictionary Indexing of Electron Channeling Patterns
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DOI：
10.1017/s1431927616012769
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发表时间：
2017-02
影响因子：
2.8
通讯作者：
Saransh Singh;M. De Graef
中科院分区：
文献类型：
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作者：
Saransh Singh;M. De Graef
摘要 基于字典的衍射图案索引方法应用于电子沟道图案（ECP）。介绍了字典方法的主要组成部分，包括广义前向投影仪（GFP）、相关探测器模型以及使用“立方体”表示对方向空间进行均匀采样的方案。 GFP 用于计算 ECP“主”模式。无导数优化算法，包括 Nelder-Mead 单纯形和二次近似的边界优化，用于确定正确的探测器参数并细化从字典方法获得的方向。该索引方法应用于多晶硅，并且与校准值非常吻合。最后，结果表明，对于一系列探测器参数，该方法导致平均定向误差为 1.0°，SD 为 0.5°。
Abstract The dictionary-based approach to the indexing of diffraction patterns is applied to electron channeling patterns (ECPs). The main ingredients of the dictionary method are introduced, including the generalized forward projector (GFP), the relevant detector model, and a scheme to uniformly sample orientation space using the “cubochoric” representation. The GFP is used to compute an ECP “master” pattern. Derivative free optimization algorithms, including the Nelder–Mead simplex and the bound optimization by quadratic approximation are used to determine the correct detector parameters and to refine the orientation obtained from the dictionary approach. The indexing method is applied to poly-silicon and shows excellent agreement with the calibrated values. Finally, it is shown that the method results in a mean disorientation error of 1.0° with 0.5° SD for a range of detector parameters.