A new experimental procedure to quantify annular dark field images in scanning transmission electron microscopy
A new experimental procedure to quantify annular dark field images in scanning transmission electron microscopy
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扫描透射电子显微镜中量化环形暗场图像的新实验程序
DOI：
10.1111/j.1365-2818.2006.01551.x
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发表时间：
2006
影响因子：
2
通讯作者：
T. Walther
中科院分区：
文献类型：
--
作者：
T. Walther
提出了一种新的方法来量化扫描电子显微镜中无晶格分辨率记录的环形暗场图像的对比度。该方法依赖于在环形暗场检测器之前使用列内能量滤光器以及作为内部探测角度的函数获取一系列能量滤波图像。在这种能量过滤的环形暗场图像中，当两种材料之间的界面的图像对比度被绘制成与相机长度的关系并外推到零(即无限散射角)时，对比度的表现与卢瑟福的散射公式(即强度尺度∝Z2)所预测的完全相同。这可以用来确定界面或薄膜的局部化学成分和有效化学宽度，而不需要任何额外的光谱方法进行校准，前提是全球化学成分已知。作为例子，详细讨论了SiGe/Si和InGaAsGe/Ge系统。
A new procedure to quantify the contrast in annular dark field images recorded without lattice resolution in a scanning transmission electron microscope is proposed. The method relies on the use of an in‐column energy filter prior to the annular dark field detector and the acquisition of a series of energy‐filtered images as a function of the inner detection angle. When the image contrast of an interface between two materials in such energy‐filtered annular dark field images is plotted vs. camera length and extrapolated to zero (i.e. infinite scattering angle), the contrast is shown to behave exactly as predicted by Rutherford's scattering formula (i.e. intensity scales ∝Z2). This can then be used to determine the local chemistry at and the effective chemical widths of interfaces or thin films without any additional spectroscopy method for calibration, provided the global chemical composition is known. As examples, the systems SiGe/Si and InGaAs/Ge are considered in detail.