Lee Ha Rim, Hwang Junhyeok, Ogawa Takashi, Jung Haewon, Yun Dal-Jae, Lee Sangsun, Park In-Yong
Scientific Instruments Performance Evaluation Team, Advanced Instrumentation Institute, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon 34113, South Korea.
Major in Nanoconvergence Measurement, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, South Korea.
Microsc Microanal. 2022 Sep 5:1-9. doi: 10.1017/S1431927622012235.
The energy distribution of an electron gun is one of the most important characteristics determining the performance of electron beam-based instruments, such as electron microscopes and electron energy loss spectroscopes. For accurate measurements of the energy distribution, this study presents a novel retarding field energy analyzer (RFEA) with the feature of an additional integrated pre-lens, which enables an adjustment of beam trajectory into the analyzer. The advantages of this analyzer are its compact size and simple electrode configuration. According to trajectory simulation theories, the optimum condition arises when the incident electron beam inside the RFEA is focused on the center of a retarding electrode. Comparing – curves depending on whether the pre-lens working or not, it is confirmed that the use of the pre-lens dramatically improves the energy resolution and efficiency of the signal acquisition process. The pre-lens RFEA was applied to characterize a Schottky electron gun under various temperatures and extraction voltages as operational conditions. When the tip temperature was increased by 50 K, we were able to measure an energy distribution broadening of 13.8 meV with the proposed pre-lens RFEA. The relative standard deviation of energy distribution was 0.7% for each working condition.
电子枪的能量分布是决定基于电子束的仪器（如电子显微镜和电子能量损失谱仪）性能的最重要特性之一。为了精确测量能量分布，本研究提出了一种新型减速场能量分析仪（RFEA），其特点是额外集成了一个预透镜，可调整进入分析仪的电子束轨迹。该分析仪的优点是尺寸紧凑且电极配置简单。根据轨迹模拟理论，当RFEA内部的入射电子束聚焦在减速电极中心时，会出现最佳条件。通过比较预透镜工作和不工作时的曲线，证实了预透镜的使用显著提高了能量分辨率和信号采集过程的效率。将预透镜RFEA应用于在不同温度和提取电压作为操作条件下对肖特基电子枪进行表征。当尖端温度升高50 K时，使用所提出的预透镜RFEA，我们能够测量到能量分布展宽为13.8 meV。每种工作条件下能量分布的相对标准偏差为0.7%。
