我国电子显微镜的研制与生产

本文记述了我国研制与生产的各种电子显微镜，主要是透射电子显微镜，扫描电子显微镜和电子探针X射线微区分析仪。1958－1959年中国科学院长春光学精密机械研究所制成了我国第一台电子显微镜，又率先自行设计研制完成100kV大型电子显微镜。根据1996－1997年国家科委组织的一项调查，当时我国拥有2021台电子显微镜，包括透射电子显微镜756台，扫描电子显微镜1165台，合计1921台。其中，进口915台，占47．6％；我国生产了100台，占52．4％，但大多为中、低档产品。中国科学院北京科学仪器研制中心KYKY，上海电子光学技术研究所和南京光学仪器厂生产的占国产1006台中的95％以上。云南大学，北京仪器厂，上海第三分析仪器厂和国营4503厂也分别研制或生产了几种透射电子显微镜和扫描电子显微镜。     

电子显微镜的现状与展望

本文扼要介绍了电子显微镜的现状与展望，透射电子显微镜方面主要有：高分辨电子显微学及原子像的观察，像差校正电子显微镜，原子尺度电子全息学，表面的高分辨电子显微正面成像，超高压电子显微镜，中等电压电镜，１２０ｋＶ，１００ｋＶ分析电镜，场发射枪扫描透射电镜及能量选择电镜等，透射电镜将又一次面临新的重大突破，扫描电子显微镜方面主要有：分析扫描电镜和Ｘ射线能谱仪，Ｘ射线波谱仪和电子探针仪，场发射枪扫描电镜和     

聚焦离子束制备透射电子显微镜样品的两种厚度判断方法

透射电镜样品的厚度是透射电镜(TEM)表征中一个重要参数,快速准确地判断样品厚度是制备高质量样品的前提.本文通过使用聚焦离子束(FIB)制备了带有厚度梯度的透射电镜样品(Si、SrTiO3和LaAlO3),并提出两种制样过程中快速判断厚度的方法.第一种通过扫描电子显微镜(SEM)的衬度变化经验地判断样品的厚度;第二种是用FIB在样品边缘切一个斜边,通过SEM测量斜边侧面的宽度用几何方法推断样品的厚度.这两种方法都通过会聚束电子衍射(CBED)和电子能量损失谱(EELS)测量的厚度作为检验标准.对比认为,样品较薄时用SEM衬度测厚比较合适;样品比较厚时用几何方法测量比较直接.     

在扫描电子显微镜中原位操纵、加工和测量纳米结构

在电子显微镜中对纳米材料和纳米结构进行原位测量是了解纳米材料的结构与性能关系的最重要手段,并且,在电子显微镜中操纵和加工纳米材料与纳米结构还可研究新结构和新器件.由于扫描电镜有大的样品室、可较容易地引入多个多种测量和操纵探针、并可配备多种探测器从多个角度对同一个样品进行表征,使得扫描电镜中的原位研究在纳米材料和纳米器件...     

Chemical bonds in damaged and pristine low-κ materials: A comparative EELS study

Chemical bonds in low-κ dielectric materials can be studied at nanometer spatial resolution using electron energy loss spectroscopy (EELS) in a monochromated transmission electron microscope (TEM). However, it is unknown to what extent TEM sample preparation and exposure to the electron beam during the measurement alter the original chemical bond state in these materials. Therefore, we are assessing the effect of different TEM sample preparation methods and beam conditions in a comparative study on low-κ dielectric materials.     

Vibrational and thermal studies of CdSe nanorods

We report the characterization of axial nanorods of cadmium selenide (CdSe), synthesized by soft chemical route using mercapto ethanol as a capping agent. Crystallization temperature of the sample is investigated using differential scanning calorimeter. Kissinger equation is applied to the thermo-grams of differential scanning calorimeter to calculate the thermal activation energy of the sample, which is found to be 1.67 eV. The rod like shape of the sample is confirmed by transmission electron microscope (TEM) and scanning electron microscope (SEM) measurement. The selected area electron diffraction pattern, high resolution TEM image and X-ray diffraction pattern of the sample indicate the cubic structure. The band gap of the sample is obtained using Tauc relation to UV–visible spectrum and found to be 1.98 eV. The photoluminescence (PL) emission spectra of the sample are measured at various excitation wavelengths. The PL spectra appear in the visible region, and the emission feature depends on the wavelength of the excitation. The Raman and infra-red spectra of the samples are analyzed to obtain the vibrational modes and normal modes of the samples.     

Local thickness and composition analysis of TEM lamellae in the FIB

High-resolution TEM image quality is greatly impacted by the thickness of the TEM sample (lamella) and the presence of any surface damage layer created during FIB–SEM sample preparation. Here we present a new technique that enables measurement of the local thickness and composition of TEM lamellae and discuss its application to the failure analysis of semiconductor devices. The local thickness in different device regions is accurately measured based on the X-ray emission excited by the electron beam in the FIB–SEM. Examples using this method to guide FIB–SEM preparation of high quality lamellae and to characterise redeposition are shown for Si and III–V semiconductor devices.     

A review of ULSI failure analysis techniques for DRAMs. Part II: Defect isolation and visualization

In this paper the basic techniques for defect isolation and visualization used in physical failure analysis of trench technique dynamic random access memories (DRAMs) are reviewed. The methods described are state-of-the-art for DRAM failure analysis down to 0.14 μm feature size and beyond. In addition to defect isolation and defect visualization from the front side of a die, the backside preparation approach is reviewed. Beginning with basic sample preparation techniques including mechanical polishing, wet and dry etching and focused ion beam (FIB) applications advantages and disadvantages of various techniques are discussed. In the second section of the paper different types of optical microscopes are covered as well as scanning and transmission electron microscopes. The imaging capabilities of the FIB systems are included in this section. Finally, some applications of scanning probe techniques especially for dopant measurements and thin oxide characterization are described.     

Scanning electron mirror microscopy and scanning electron microscopy of integrated circuits

The recently developed scanning electron mirror microscope (SEMM) is compared with other types of electron microscopes, such as the electron mirror microscope (EMM) and the scanning electron microscope (SEM), for examining integrated circuits. Potential advantages of the SEMM include high resolution, elimination of electron bombardment damage, and high sensitivity of voltage gradients, magnetic fields, and topography. Preliminary observations of integrated, circuits obtained with the feasibility SEMM at various specimen potentials are discussed.     

MOCVD法侧向外延生长高质量GaN

利用金属有机物气相外延法(MOCVD)，在GaN/蓝宝石复合衬底上，采用侧向外延生长技术制备出高质量的GaN外延膜，并对其进行扫描电镜、X射线双晶衍射、透射电镜测量和分析. 发现完全合并后的GaN外延层的表面平整，晶体质量较衬底有大幅的提高，透射电镜进行微区位错观察发现窗口区穿透位错大部分发生转向，侧向生长区下方的穿透位错被掩膜阻断.     

草甘膦对大豆超微结构及光合指标影响的研究

利用透射电镜和扫描电镜,研究转基因抗草甘膦大豆和非抗草甘膦大豆东农42喷施草甘膦后大豆光合器官叶片的超微结构变化,并结合叶绿素含量、光合速率的测定,对比分析了抗草甘膦大豆和东农42在结构及生理功能上对草甘膦的表现及结构与功能变化的关系.研究结果表明抗草甘膦大豆对草甘膦的胁迫可以看作是一种适应.它首先经过一个损伤期,然后进入修复期,最终到基本恢复,表现出对草甘膦的抗性.而东农42的光合系统及光合功能则被草甘膦所彻底破坏.本文对其原因进行探究,以期为转基因作物育种尤其是超微结构方面的研究及草甘膦作用机理的研究有一定帮助.     

煤岩样品TEM超薄切片制备方法研究

本文作者以泥炭、褐煤、烟煤及无烟煤为例,探讨了超薄切片制备方法对不同煤阶样品的适用性。在采用包埋切片法制备煤岩样品TEM超薄切片时,首先通过浸解离析方法和HCl、HF逐级化学浸蚀方法使煤中自然共生组合的有机显微组分离析及脱除无机矿物质;利用光学显微镜(透射/反射模式)镜检离析显微组分后,使用SPI812树脂对挑出的单一显微组分块体渗透及包埋聚合。显微组分块体形态学及嵌布矿物成分分析使用扫描电子显微镜的低真空二次电子像模式和EDS面分布分析模式;利用透射电子显微镜检查超薄切片效果。实验表明采用上述方法制备煤岩TEM超薄切片样品的成功率较高,并且能够比较真实的再现显微组分的微观结构。     

FIB-SEM-Ar“三束”显微镜

FIB-SEM-Ar"三束"显微镜在FIB/SEM装置的平台上附加了降低样品损伤的低能Ar离子枪,首次实现了通过一台仪器完成高质量的透射电子显微镜TEM的样品制备。简化了样品整个加工的过程,同时大大提高了加工精度和工作效率。对"三束"显微镜做了介绍。     

纳米结构可重入扫描隧道显微镜系统的研制

本文简介我们最近研制成功的超高真空（ＵＨＶ）扫描隧道显微镜（ＳＴＭ）系统。该系统由于同时安装有扫描电子显微镜（ＳＥＭ），可以使ＳＴＭ的针尖在ＳＥＭ的引导下移到样品表面上任一感兴趣的地方去研究那时的纳米细节，从而使它的ＳＴＭ具有纳米结构可重入性。该系统还有一些特有的样品制备功能，可用于许多有价值的研究 。     

钛基复合材料的离子抛光工艺适用性研究

金属基复合材料的制样难点在于基体和增强相物理性能差异大,采用机械-化学抛光、电解抛光等传统方法制样效率较低。离子抛光的制样优势在于可通过程序控制,实现对复合材料的整体加工,减小界面浮凸,从而提高制样效率。作者在前期研究中得到了最佳离子抛光工艺参数,将此系列参数应用于不同增强相含量钛基复合材料的扫描电镜制样中,对比观察微观形貌、硬度和晶粒取向分布图。实验表明,采用此工艺参数得到的SEM电子背散射衍射、EBSD分析结果标定率高,可应用于此种类钛基复合材料的扫描电镜样品制备中,验证了离子抛光工艺参数的适用性。     

透射电镜电学测试样品杆与扫描电镜联合系统的搭建

透射电子显微镜电学测试样品杆是用于透射电子显微镜中测试样品外场加载下电学性能的专用仪器。本文介绍通过对法兰及其它对接接口的系列设计,使该系统可应用于扫描电子显微镜中。该系列设计改造,能够大大拓展该电学测试系统的应用范围。以单根Si纳米线为例,在扫描电子显微镜中利用该电学测试系统实现Si纳米线弯曲变形下电输运性能的研究。     

Ion beam preparation of passivated copper integrated circuit structures for electron backscatter diffraction/orientation imaging microscopy analysis

Passivation layers were removed from copper interconnect lines using a broad beam ion source in preparation for electron backscatter diffraction (EBSD) and orientation imaging microscopy (OIM) analysis. Results were obtained on interconnect lines with widths as small as 0.25 μm. The effects of ion beam energy and scanning electron microscope (SEM) acceleration voltage on the quality of the results obtained are examined and explained. The use of thin amorphous carbon coatings to reduce specimen charging during orientation data collection is also discussed.     

用侧向外延生长法降低立方相GaN中的层错密度

尝试用侧向外延(ELOG)方法来降低立方相GaN中的层错密度.侧向外延是在SiO2/GaN/GaAs图形衬底上进行的,对生长所得的立方相GaN外延层用扫描电子显微镜(SEM)和透射电子显微镜(TEM)进行了观察和分析,TEM的平面像表明经过ELOG方法生长后,立方相GaN外延层中的层错密度由侧向外延生长前的5×109cm-2降低至生长后的6×108cm-2.双晶X射线衍射(DCXRD)测量给出侧向外延前后外延层ω扫描(002)衍射摇摆曲线的半高宽(FWHM)分别为33′和17.8′,表明晶体质量有了较大改善.对立方相GaN侧向外延过程中层错减少的机制进行了讨论.     

扫描电子显微镜在植物中的应用研究进展

扫描电子显微镜(SEM)作为一种行之有效的科研分析工具,可对多种植物材料的表面形貌进行观察研究,具有较广的应用范围。本文论述了扫描电子显微镜样品的制备以及在植物花器官、种子表皮、种子形态、叶片表皮、内含物、病原体以及在植物细胞水平的研究进展,并对今后扫描电子显微镜的应用前景进行了展望,以期为利用SEM从事植物研究的科研人员提供一定的研究思路。     

FIB-SEM双束技术简介及其部分应用介绍

聚焦离子束( FIB)与扫描电子显微镜( SEM)耦合成为FIB-SEM双束系统后,通过结合相应的气体沉积装置,纳米操纵仪,各种探测器及可控的样品台等附件成为一个集微区成像、加工、分析、操纵于一体的分析仪器。其应用范围也已经从半导体行业拓展至材料科学、生命科学和地质学等众多领域。本文介绍了双束系统中的一些关键概念及基本原理并综述了其在材料科学领域的一些典型应用,包括透射电镜( TEM)样品制备,微纳尺度力学测试样品制备以及材料三维成像及分析。