环境扫描电子显微镜的关键技术

环境扫描电子显微镜在气体压力高达6600Pa，温度高达1500℃，具有任何气体种类的多气环境里，都可提供高分辨率的二次电子成像。如此优良性能的获得，取决于两项新技术：一是将柱形电子导管的真空环境与样品室环境分开；二是使用了一个在样品室非真空环境下仍然能起作用的二次电子探头。这些问题的解决是开发ESEM的关键。     

扫描电子显微镜成像信号分析

介绍了扫描电子显微镜（SEM）的基本工作原理,着重分析了在SEM初始电子束作用下,各种成像信号产生的方式及其特点,确定二次电子信号因成像分辨率高、携带成像信息丰富而成为SEM的最终信号源。针对此信号在实际应用中暴露出的缺陷,介绍了解决办法,从而使SEM的成像性能得以大幅提高,使用范围大为扩展。     

扫描电子显微镜

随着科学技术的发展进步,人们不断需要从更高的微观层次观察、认识周围的物质世界。细胞、微生物等微米尺度的物体直接用肉眼观察不到,显微镜的发明解决了这个问题。目前,纳米科技成为研究热点,集成电路工艺加工的特征尺度进入深亚微米,所有这些更加微小的物体光学显微镜也观察不到,必须使用电子显微镜。电子显微镜可分为扫描电子显微镜简称扫描电镜(SEM)和透射电子显微镜简称透射电镜(TEM)两大类。     

环境扫描电子显微镜中真空系统特点及成像信号分析

环境扫描电子显微镜(ESEM)是针对常规扫描电子显微镜(SEM)在使用过程中暴露出来的一些重大缺陷而设计的.它淘汰了SEM中繁琐、复杂的样品准备工作,扩大了仪器的使用范围,并使图像更清晰.着重介绍了ESEM的工作原理、与此有关的真空系统构成及成像信号分析.     

基于扫描电子显微镜的二次电子发射系数测量

二次电子发射特性对许多领域的真空器件有着重要的影响,准确测量二次电子发射系数至关重要。本文介绍了一种基于扫描电子显微镜的二次电子发射系数的测量方法。利用扫描电子显微镜电子束流的高稳定性和电子能量的宽范围可调的特性,引入法拉第杯样品台,通过改变电子束扫描速度,放大倍数及聚焦状态等电镜参数,对平滑Ag的二次电子发射系数进行测量。结果显示,平滑Ag的二次电子发射系数不受电镜参数影响,且与参考文献测量结果相符合。本测试方法对于研究材料宽电子能量范围的二次电子发射特性具有重要的参考意义。     

高效消除色差的扫描电子显微镜——Magellan

扫描电子显微镜是1965年发明的先进的显微结构研究工具,主要是利用二次电子信号成像来观察样品的表面形态,即用极狭窄的电子束去扫描样黼,通过电子束与样品的相互作用产生各种效应,其中主要是样品的二次电子发射。二次电子能够产生样品表面放大的形貌像,这个像是在样品被扫描时按时序建立起来的,即使用逐点成像的方法获得放大像。     

扫描电子显微镜低真空模式的应用

低真空模式是扫描电镜的一种新型观测模式,它的最大特点是可以对不导电样品直接进行观察。这样既避免了不导电样品表面由于电荷累积产生的假象,又省去了对样品表面进行导电喷镀,还有利于不导电样品其他信息的检测与分析。此外,扫描电镜低真空模式还可以对低致密度或多孔样品进行直接观察,这是高真空模式无法取代的。     

环境扫描电子显微镜的特性及应用概况

简要叙述了环境扫描电子显微镜的原理，着重介绍了它的特性和在国内外应用的概况。与普通的扫描电子显微镜相比，它具有能直接检测不导电样品和含油含水样品的独特性能，为扫描电子显微镜的应用开拓了新的领域。     

SciosTM扫描电子显微镜

超高分辨率成像和高吞吐量的2D和3D的分析性能。FEIScios是一个Dual—BeamT”系统,可提供出色的性能,适用于范围广泛的样品一即使是磁性或非导电材料。其旨在增加吞吐量、精度和易用性的创新功能,FEIScios是理想的跨学术,政府和工业环境中的先进研究应用工具。     

氧环境扫描电子显微分析:消除绝缘材料荷电效应的新方法

在环境扫描电镜(ESEM)中注入氧气,减少和消除绝缘样品表面在电子束辐照下产生的荷电效应.二次电子像的观察显示,在压力为130Pa～600Pa的ESEM中,氧气对Al2O3、Al(OH)3等氧化物、氢氧化物及生物样品的荷电补偿效果,优于常用的水蒸汽环境.通过吸收电流Ia的实时测试,评价了氧环境的荷电补偿效果.采用氧气减少表面荷电基于一个新的概念:在电子束的辐照下,电子受激解吸可造成表面氧亏损,使能带产生畸变,形成捕获电子的势阱.氧环境提供的氧离子可实现对氧空位的修复,从而消除了荷电效应.     

Calibrating a scanning electron microscope in two coordinates by the use of one certified dimension

A method is proposed for calibrating a scanning electron microscope that corresponds completely to national standards providing unification of measurements in nanotechnology. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 18–20, June, 2008.     

层析扫描声学显微镜相关算法及其比较

为了获得物体内部清晰的三维图像,提高激光扫描声学显微镜的分辨能力,在激光扫描声学显微镜原理的基础上,阐述了层析扫描声学显微镜的结构和工作方式。结合层析技术并且根据超声波在介质中的传播规律介绍了三种层析算法:频域内的插值算法;往返传播算法;滤波反向传播算法。最后通过理论和实验比较,结果表明:往返传播算法通过对滤波函数进行改进,在有限孔径的前提下,应用于层析扫描声学显微镜时比其它两种算法可以获得更好的重建图像效果。     

Design and imaging properties of a laser scanning microscope with a position-sensitive detector

An economical method of microscopic image formation that employs a raster-scanning laser beam focused on a sample, while a non-imaging detector receives the scattered light, is presented. The images produced by this method are analogous to the scanning electron microscopy with visible effects of shadowing and reflection. Compared to a conventional wide-field imaging system, the system allows for a greater flexibility, as the variety of optical detectors, such as PMT and position-sensitive quadrant photodiode can be used to acquire images. The system demonstrates a simple, low-cost method of achieving the resolution on the order of a micron. A further gain in terms of resolution and the depth of focus by using Bessel rather than Gaussian beams is discussed.     

Compression test of a single carbon fiber in a scanning electron microscope and its evaluation via finite element analysis

A longitudinal compression test for a single polyacrylonitrile-based carbon fiber (T300) was performed using a scanning electron microscope. The compressive stress/strain behavior was initially linear, but subsequently became nonlinear. The longitudinal tangent modulus decreased with increasing compressive strain. A cyclic compression test revealed that the T300 carbon fiber deformed elastically up to ~90% compressive strength. The variability in the compressive strength was evaluated using Weibull analysis. The representative compressive strength of the T300 carbon fiber was nearly the same as the tensile strength. The compressive strength of the T300 carbon fiber was almost same as that of the high-tensile strength T800S carbon fiber. Finite element analysis was performed to investigate the validity of the test method. The results showed that the longitudinal compressive stress on the carbon fiber varied during longitudinal compressive loading. The maximum longitudinal compressive stress in the carbon fiber was slightly higher than the average compressive strength applied at the end. However, the variability in the measured compressive strength was much higher than that in the longitudinal compressive stress on the carbon fiber, which does not affect the former.     

A test object with three certified linewidth dimensions for a scanning electron microscope

A test object for a scanning electron microscope, which has a trapezoidal profile of the relief with large angles of inclination of the side walls, is developed. The test object contains elements (protrusions) with three certified dimensions of the linewidth, situated in two mutually perpendicular directions. Translated from Izmeritel'naya Tekhnika, No. 9, pp. 49–52, September, 2008.     

Liquid helium cooled sample stage for scanning electron microscope

A cryogenic stage is described for use with a Cambridge S4-10 scanning electron microscope. The stage is operated with liquid helium in direct contact with the back of the sample to be irradiated by the electron beam. This bath cryostat principle will work at temperatures between 1.5 K and 4.2 K with good cooling performance. The installation of the stage within the microscope does not require any modification of the microscope chamber or the detector arrangement. A precision adjustment of the sample perpendicular to the electron beam is achieved by micrometric screws.     

Accuracy in linear dimensions measurement in scanning electron microscopes in microtechnology and nanotechnology

A study has been made on the effects of scanning electron microscope parameters on the accuracy in measuring the linear dimensions in microtechnology and nanotechnology. Definitions are given of the errors with which these parameters should be known for using such microscopes in such technologies. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 15–18, June, 2008.     

扫描电子显微镜图像漂移的实时矫正方法

为解决扫描电子显微镜(SEM)由于电子束漂移、电磁干扰等原因导致的图像漂移问题,提出基于ORB结合PROSAC的图像漂移矫正算法。首先采用ORB算法对基准图像和实时图像进行特征检测,然后利用汉明距离与交叉匹配实现特征的初匹配,再结合RANSAC的优化算法PROSAC计算帧间的单应矩阵,利用单应矩阵映射剔除外点后重新迭代计算出最终的精确单应矩阵,最后利用单应矩阵的透视变换实现SEM图像漂移实时矫正。通过实验证明,该算法不仅精度高,而且能够满足SEM实时处理的要求。     

Classification of test objects for use in calibration of scanning electron microscopes in the nanometric range

A classification of test objects for use in calibration of scanning electron microscopes in the nanometric range is created. The shape of the relief profile of the elements of the test objects and the relationship of the profile to the physical mechanisms underlying the formation of the signal generated by a microscope functioning in a mode for the collection of secondary slow electrons is used as the basis of the classification. Translated from Izmeritel’naya Tekhnika, No. 2, pp. 22–26, February, 2009.