Agemura Toshihide, Sekiguchi Takashi
Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1 Namiki, Tsukuba 305-0044, Japan.
International Center for Materials Nanoarchitectoronics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
Microscopy (Oxf). 2018 Feb 1;67(1):18-29. doi: 10.1093/jmicro/dfx124.
Collection efficiency and acceptance maps of typical detectors in modern scanning electron microscopes (SEMs) were investigated. Secondary and backscattered electron trajectories from a specimen to through-the-lens and under-the-lens detectors placed on an electron optical axis and an Everhart-Thornley detector mounted on a specimen chamber were simulated three-dimensionally. The acceptance maps were drawn as the relationship between the energy and angle of collected electrons under different working distances. The collection efficiency considering the detector sensitivity was also estimated for the various working distances. These data indicated that the acceptance maps and collection efficiency are keys to understand the detection mechanism and image contrast for each detector in the modern SEMs. Furthermore, the working distance is the dominant parameter because electron trajectories are drastically changed with the working distance.
研究了现代扫描电子显微镜（SEM）中典型探测器的收集效率和接受度图。对从样品到位于电子光轴上的透镜透过式和透镜下探测器以及安装在样品室上的埃弗哈特-索恩利探测器的二次电子和背散射电子轨迹进行了三维模拟。接受度图绘制为不同工作距离下收集电子的能量与角度之间的关系。还针对各种工作距离估计了考虑探测器灵敏度的收集效率。这些数据表明，接受度图和收集效率是理解现代扫描电子显微镜中每个探测器的检测机制和图像对比度的关键。此外，工作距离是主导参数，因为电子轨迹会随着工作距离而发生剧烈变化。
