Kriaa Hana, Guitton Antoine, Maloufi Nabila
Arts et Métiers-LEM3, Université de Lorraine-CNRS, 7 rue Félix Savart, 57070 Metz, France.
Laboratory of Excellence on Design of Alloy Metals for Low-mAss Structures (DAMAS), Université de Lorraine, 57073 Metz, France.
Materials (Basel). 2021 Mar 30;14(7):1696. doi: 10.3390/ma14071696.
In a scanning electron microscope, the backscattered electron intensity modulations are at the origin of the contrast of like-Kikuchi bands and crystalline defects. The Electron Channeling Contrast Imaging (ECCI) technique is suited for defects characterization at a mesoscale with transmission electron microscopy-like resolution. In order to achieve a better comprehension of ECCI contrasts of twin-boundary and stacking fault, an original theoretical approach based on the dynamical diffraction theory is used. The calculated backscattered electron intensity is explicitly expressed as function of physical and practical parameters controlling the ECCI experiment. Our model allows, first, the study of the specimen thickness effect on the channeling contrast on a perfect crystal, and thus its effect on the formation of like-Kikuchi bands. Then, our theoretical approach is extended to an imperfect crystal containing a planar defect such as twin-boundary and stacking fault, clarifying the intensity oscillations observed in ECC micrographs.
在扫描电子显微镜中，背散射电子强度调制是类菊池带和晶体缺陷对比度的起源。电子通道对比度成像（ECCI）技术适用于在中尺度上以类似透射电子显微镜的分辨率对缺陷进行表征。为了更好地理解孪晶界和堆垛层错的ECCI对比度，采用了一种基于动力学衍射理论的原始理论方法。计算出的背散射电子强度明确表示为控制ECCI实验的物理和实际参数的函数。我们的模型首先允许研究样品厚度对完美晶体中通道对比度的影响，进而研究其对类菊池带形成的影响。然后，我们将理论方法扩展到包含平面缺陷（如孪晶界和堆垛层错）的不完美晶体，阐明了在ECC显微照片中观察到的强度振荡。
