Retrieving overlapping crystals information from TEM nano‐beam electron diffraction patterns
Retrieving overlapping crystals information from TEM nano‐beam electron diffraction patterns
复制标题
从 TEM 纳米束电子衍射图案中检索重叠晶体信息
作者：
A. Valery;Edgar F. Rauch;L. Clément;F. Lorut
使用透射电子显微镜 (TEM) 获得的衍射图案包含与叠加在薄箔中并被电子束穿过的所有晶体相关的布拉格反射。对于基于 TEM 的取向和相位表征技术，这些信号的非解离通常被认为是衍射图案索引的主要限制。提出了一种识别与不同但重叠的颗粒相关的信息的新方法。它包括在重新索引衍射图案之前减去主晶体的特征。该方法与标准自动晶体取向映射工具（ACOM-TEM）中使用的模板匹配算法相结合。该方法的功能通过堆叠在单晶硅层上的镍硅薄膜的表征来说明。然后，对包含多晶钨电触点的 70 nm 厚薄箔应用减法索引循环，显示了该技术识别小非主要晶粒的能力。
The diffraction patterns acquired with a transmission electron microscope (TEM) contain Bragg reflections related to all the crystals superimposed in the thin foil and crossed by the electron beam. Regarding TEM‐based orientation and phase characterisation techniques, the nondissociation of these signals is usually considered as the main limitation for the indexation of diffraction patterns. A new method to identify the information related to the distinct but overlapped grains is presented. It consists in subtracting the signature of the dominant crystal before reindexing the diffraction pattern. The method is coupled to the template matching algorithm used in a standard automated crystal orientation mapping tool (ACOM‐TEM). The capabilities of the approach are illustrated with the characterisation of a NiSi thin film stacked on a monocrystalline Si layer. Then, a subtracting‐indexing cycle applied to a 70 nm thick thin foil containing polycrystalline tungsten electrical contacts shows the capability of the technique to recognise small nondominant grains.