Contrast and resolution versus specimen thickness in low energy scanning transmission electron microscopy
Contrast and resolution versus specimen thickness in low energy scanning transmission electron microscopy
复制标题
低能扫描透射电子显微镜中的对比度和分辨率与样品厚度的关系
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
P. Merli
中科院分区：
文献类型：
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作者：
V. Morandi;P. Merli
本文报道了低能量扫描透射电子显微镜中对比度和分辨率随试样厚度变化的理论和实验研究。由于标本后成像透镜的缺失，有可能具有分辨率的图像由探针尺寸定义，使用非常宽的收集角度，独立于传输电子的能量损失。可观察试件厚度的基本限制由信噪比表示，即光束电流的强度。所研究的样品是半导体多层，Sb沉淀在Si植入样品中。对平行于电子束穿过整个样品的层的观察指出，只有一小部分层，即靠近表面的层，引起图像对比度，而下面的部分，由于拓宽的结果，探针直径比层本身大，降低了对比度。与最近的结果相似，在扫描…
A theoretical and experimental investigation of contrast and resolution versus specimen thickness in scanning transmission electron microscopy at low energy is reported. Due to absence of postspecimen imaging lenses it is possible to have images with a resolution defined by the probe size using very wide collection angles and independent of the energy loss of the transmitted electrons. The fundamental limitation in observable specimen thickness is represented by the signal to noise ratio, i.e., the intensity of the beam current. The investigated specimens are semiconductor multilayers and Sb precipitates in a Si implanted specimen. The observations of layers crossing the whole specimens parallel to the electron beam point out that only a small portion of them, the one close to the surface, causes the image contrast, while the portion below, where the probe diameter, as a consequence of the broadening, is larger than the layer itself, reduces the contrast. A similarity with recent results, achieved in scan...