Estimation of Energy Acceptance of SE Detectors in Scanning Electron Microscopy
Estimation of Energy Acceptance of SE Detectors in Scanning Electron Microscopy
复制标题
扫描电子显微镜中 SE 探测器能量接受度的估计
DOI：
10.1017/s1431927613007976
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
K. Kumagai and T. Sekiguchi
中科院分区：
文献类型：
--
作者：
Hideyuki Nakanishi;川端友人・菊田郁夫・瀬川浩代・中西英行・則末智久・宮田貴章;中西英行・川端友人・菊田郁夫・瀬川浩代・則末智久・宮田貴章;内藤康彬・松本郁子・中西英行・則末智久・宮田貴章;Hideyuki Nakanishi;松本郁子・内藤康彬・中西英行・則末智久・宮田貴章;Hideyuki Nakanishi;Hideyuki Nakanishi;Hideyuki Nakanishi;Hideyuki Nakanishi;中西英行;中西英行;中西英行;中西英行・菊田郁夫・瀬川浩代・則末智久・宮田貴章;菊田郁夫・中西英行・瀬川浩代・則末智久・宮田貴章;中西英行;中西英行;K. Fukuda and K. Kumagai;K. Kumagai and T. Sekiguchi
在现代扫描电子显微镜（SEM）中，光谱信号检测已经引起越来越多的关注，因为它有可能通过选择信号电子能量来强调我们感兴趣的图像对比度[1]。根据这一点，我们从二次电子（SE）能量的角度研究了SE成像[2，3]。由于在实际扫描电镜中设置的SE探测器收集了样品以能量E和发射角θ发射的一部分电子，因此我们必须了解待检测的E和θ的可能组合，即探测器接受度G（E，θ）。然而，在大多数情况下，G（E，θ）是不清楚的，只有少数结果通过模拟得到[4]。因此，如果我们发展一种简单易行的方法来估计G（E，θ），这对分析SE图像对比度是非常有用的。作为这样做的第一步，我们已经评估了在所谓的“双子柱”中设置的环形透镜SE探测器的能量接受度。通过在p-Si衬底上沉积Cr、Fe、Cu、Ag、Au（各200 nm）和Pt（300 nm）等金属层，制作了一个由多个金属层组成的模型样品，并将其与标准SE谱进行对比，以推断SE探测器的能量接收能力。用Ar+离子束进行截面抛光后，尽可能快地将样品放入SEM室中。我们使用配备有场发射电子枪（Omicron Nanotechnologies，德国）的UHV-SEM进行SE观察。待评价的SE探测器是位于电子枪柱内部的环形透镜内SE探测器[5，6]。扫描电镜室的真空度保持在10-7 Pa以下，这使我们能够无污染地观察样品。
In modern scanning electron microscopy (SEM), spectroscopic signal detection has been attracting increasing attention, because it has potential to emphasize the image contrast of our interest by selecting signal electron energy [1]. According this point, we have studied secondary electron (SE) image formation in aspect of SE energy [2, 3]. Since SE detector set in actual SEM collects a part of electrons emitted from specimen with energy E and emission angle θ, we have to understand possible combinations of E and θ to be detected, ie detector acceptance G (E, θ). In most cases, however, G (E, θ) is not known clearly except few results obtained by simulation [4]. Thus, if we develop a simple and easy method to estimate G (E, θ), it is very useful to analyze SE image contrast. As a first step to do this, we have evaluated the energy acceptance of an annular in-lens SE detector set in so-called “Gemini column.” We fabricated a specimen consists of several metal layers, and studied their SE image contrast comparing with standard SE spectrum to deduce energy acceptance of the SE detector.A model specimen was fabricated by depositing layers of Cr, Fe, Cu, Ag, Au (200 nm thick each) and Pt (300 nm thick) onto p-Si substrate. After the cross section polishing with Ar+ ion beam, the specimen was put in SEM chamber as immediately as possible. We used an UHV-SEM equipped with field emission electron gun (Omicron Nanotechnologies, Germany), for SE observation. The SE detector to be evaluated was an annular in-lens SE detector located inside of the electron gun column [5, 6]. The vacuum of SEM chamber was kept lower than 10-7 Pa, which enables us to observe specimens without contamination.