S-4700型扫描电子显微镜的结构与操作注意事项

主要介绍了日立S-4700型扫描电子显微镜基本结构特点,以及该仪器在操作过程或日常维护中需要注意的几个方面。扫描电子显微镜的结构主要包括真空系统、电子光学系统和信息接收显示系统3个主要部分。本文针对S-4700型扫描电子显微镜分别对如何保证良好的真空条件;电子光学系统中的电子枪、电子透镜、扫描系统和消象散装置的结构与工作原理;以及信息接收显示系统中的二次电子检测器的结构与工作原理进行了简单的介绍。对应于以上的结构介绍,对仪器在日常维护中可能出现的问题进行了简单的分析。     

Low-cost image-capture system for a scanning electron microscope

We describe a PC-based active-capture system for recording digital images from a scanning electron microscope. The system is based on a National Instruments data-acquisition board and a Pentium computer, controlled by software that we have written in Visual Basic.     

Development of a scanning electron microscope with a two detector system

The authors consider the design feature of a prototype scanning electron microscope which they have constructed. The article serves as basic revision of the function of all the components in an SEM system, as well as illustrating the authors' choice of alternatives. A distinctive aspect of the present instrument is that the idea of incorporating two detector systems for SE was present from the beginning of the planning stages. The applicability of this system is illustrated by compositional (A + B) and topographic (A − B) SE images.     

The effect of radio-frequency sputter ion etching and ion-beam etching on biological material: a scanning electron microscope study

Mammalian and avian cells have been examined in the scanning electron microscope either after prior radio-frequency sputter ion etching with different ions (hydrogen, helium, argon, oxygen) or after argon ion bombardment in the SEM. Whilst the pattern of erosion is similar in the different specimens, the etching pattern varies with the different gases. It has not been possible to relate the etching patterns to characteristic subsurface structures.     

A distortion-free low-magnification stage for the Hitachi HU-11B electron microscope

A low-magnification stage is described which facilitates the production of distortion-free images in the Hitachi HU-11B electron microscope in the range × 150–2000. The construction and method of operation of the device together with its advantages and potential uses in the material and biological sciences are considered.     

A flexible instrument control and image acquisition system for a scanning electron microscope

We have developed an instrument control and image acquisition system for use with scanning electron microscopes. By making the system flexible over a wide range of operating voltages, scan generation and image acquisition modes can be easily accommodated to a wide range of instruments. We show the implementation of this system for use with a custom‐built low‐voltage scanning electron microscope. We then explore the simple modifications that are required for control of two instruments intended for use as free electron lasers.     

An automated image alignment system for the scanning electron microscope

We have developed an automated image alignment system for the scanning electron microscope (SEM). This system enables specific locations on a sample to be located and automatically aligned with submicron accuracy. The system comprises a sample stage motorization and control unit together with dedicated imaging electronics and image processing software. The standard SEM sample stage is motorized in the X and Y axes with stepping motors which are fitted with rotary optical encoders. The imaging electronics are interfaced to beam deflection electronics of the SEM and provide the image data for the image processing software. The system initially moves the motorized sample stage to the area of interest and acquires an image. This image is compared with a reference image to determine the required adjustments to the stage position or beam deflection. This procedure is repeated until the area imaged by the SEM matches the reference image. A hierarchical image correlation technique is used to achieve submicron alignment accuracy in a few seconds. The ability to control the SEM beam deflection enables the images to be aligned with an accuracy far exceeding the positioning ability of the SEM stage. The alignment system may be used on a variety of samples without the need for registration or alignment marks since the features in the SEM image are used for alignment. This system has been used for the automatic inspection of devices on semiconductor wafers, and has also enabled the SEM to be used for direct write self-aligned electron beam lithography.     

The scanning low-energy electron microscope: First attainment of diffraction contrast in the scanning electron microscope

Using small Pb crystals deposited in situ on a partially contaminated Si (100) crystal, we demonstrate that a commercial scanning electron microscope (SEM) can easily be converted into a scanning low-energy electron microscope (SLEEM). Although the contrast mechanism is much more complicated than that in nonscanning LEEM because not only one diffracted monochromatic beam and its close environment are used for imaging, but several diffracted beams and a wide energy spectrum of electrons of different origin (secondary electrons, inelastically andelastically scattered electrons) are used, SLEEM is a valuable addition to the standard SEM because it provides an additional structure- and orientation-sensitive contrast mechanism in crystalline materials, a low sampling depth, and high intensity at low energies.     

A wet stage modification to a scanning electron microscope.

A modification to the vacuum system of a JSM2 scanning electron microscope has enabled hydrated specimens to be placed inside the specimen chamber of the instrument and to be surronded by water vapour at a pressure up to approximately I 3-kPa (10 Torr). The surface topography was observed by detecting the backscattered electrons using a wide angle backscattered electron detector placed close to the specimen. The microscope was operated in the normal scanning mode which allowed the examination of the surface topography of the specimens, whilst still retaining the depth of focus which is a feature of the SEM. This modification has enabled a resolution of approximately 0.2 mum to be obtained from biological specimens partially immersed in water at temperatures just above 0 degrees C.     

A scanning near-field optical microscope having scanning electron tunnelling microscope capability using a single metallic probe tip

A new microscope system that has the combined capabilities of a scanning near-field optical microscope (SNOM) and a scanning tunnelling microscope (STM) is described. This is achieved with the use of a single metallic probe tip. The distance between the probe tip and the sample surface is regulated by keeping the tunnelling current constant. In this mode of operation, information about the optical properties of the sample, such as its refractive index distribution and absorption characteristics, can be disassociated from the information describing its surface structure. Details of the surface structure can be studied at resolutions smaller than the illumination wavelength. The performance of the microscope is evaluated by analysing a grating sample that was made by coating a glass substrate with gold. The results are then compared with the corresponding SNOM and STM images of the grating.     

A robust micromanipulator for the scanning electron microscope.

A simple device for holding and moving mechanical tools in the region of a sample being viewed in the scanning electron microscope is described. The unit has a 20:1 mechanical reduction and when fitted with a tungsten carbide dental chisel, it is sufficiently rigid to cut biological hard tissues. Alternately, when fitted with an electro-etched tungsten needle, it can be used, in conjunction with specimen stage controls, to remove individual cells from the surface of soft tissues. Examples of these applications are illustrated.     

Mechanical scanning of the specimen in the scanning electron microscope

A scanning electron microscope (SEM) system equipped with a motor drive specimen stage fully controlled with a personal computer (PC) has been utilized for obtaining ultralow magnification SEM images. This modem motor drive stage works as a mechanical scanning device. To produce ultra-low magnification SEM images, we use a successful combination of the mechanical scanning, electronic scanning, and digital image processing techniques. This new method is extremely labor and time saving for ultra-low magnification and wide-area observation. The option of ultra-low magnification observation (while maintaining the original SEM functions and performance) is important during a scanning electron microscopy session.     

Application of an environmental scanning electron microscope to micromechanical fabrication

Current advanced methods of micromechanical fabrication require expensive tooling or are restricted to the fabrication of lateral-shaped microstructures. To overcome these limitations, recent efforts have usedmicroscale additive freeform fabrication (AFF) methods to prototype micromechanical structures. However, these laser-based methods are limited in resolution. To improve the resolution of microscale AFF methods, an environmental scanning electron microscope (ESEM) was used to prototype several electron-beam (EB)-based microscale AFF processes. The results showed that the ESEM is capable of demonstrating process feasibility for EB-based microscale AFF.     

Design and fabrication of a scanning electron microscope using a finite element analysis for electron optical system

In this paper, we describe the design and fabrication of a thermionic scanning electron microscope (SEM) and examine its characteristics analytically. In the design process, the dimensions and capacity of the SEM components, such as the electron column, lenses, and apertures, were determined using finite element analysis. All components were integrated systematically during fabrication in order to achieve the maximum performance by adjusting the lens parameters, high voltage source, and image calibration methods. As a result, a thermionic SEM image with high resolution was achieved. We discuss the primary considerations required to achieve a high-performance image.     

A case of Leukonychia with scanning electron microscope observation

Leukonychia is a medical term for white discoloration appearing on nails. The pathophysiologic mechanisms that cause white discoloration are not entirely clear. We processed a case of leukonychia with scanning electron microscope observation and found many crispy, obviously dissociated "layers" in the lower part of the white nail plate. The dissociated "layers" were composed of thick, loose, coarse keratin bundles intertwined with each other. We believe the dissociated "layers" are related to the clinically noted white discoloration appearing on the nails.     

A simply constructed heating stage for the scanning electron microscope

An easily constructed heating stage has been designed for a Cambridge Scientific Instruments' Stereoscan Scanning Electron Microscope. This heating stage is capable of reaching temperatures of at least 1273 K. The stage is a simple design which can easily be built from non-magnetic stainless steel and a natural stone consisting mainly of pyrophyllite. All heat shielding is made from these materials without the need for any liquid coolant surrounding the stage. The use of this heating stage as an instrument for the study of morphological changes during heating processes up to 1273 K is described briefly.     

Observation of an undecagold cluster compound in the scanning transmission electron microscope

A water-soluble undecagold cluster compound has been shown to be visible in moderate dose images (10⁴ electrons/nm²) obtained with the scanning transmission electron microscope (STEM). The properties of this compound render it potentially useful as a marker for specific sites within biological molecules.