Field Emission SEM with a Newly Developed FEGUN and Conical Strongly Excited Objective Lens

2000 ◽  
Vol 6 (S2) ◽  
pp. 764-765
Author(s):  
H. Kazumori ◽  
A. Yamada ◽  
M. Mita ◽  
T. Nokuo ◽  
M. Saito
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Secondary Electron ◽  
Objective Lens ◽  
Probe Current ◽  
Large Samples ◽  
Low Emission ◽  
Working Distance ◽  
Scanning Electron

A newly developed cold FE-GUN which enables to us to obtain large probe current and low emission noise, and conical strongly excited objective lens has been installed on the JSM-6700F Scanning Electron Microscope (SEM). In the range of accelerating voltages from 0.5 to 15kV, this instrument has got much better resolution as compared with in-lens type SEM (Ohyama et al 1986)(Fig. 1). We can obtain high-resolution secondary electron images with large samples (ex. 150mm ϕ×10mmH).Our old type objective lens (Kazumori et al 1994) has the limitation of working distance (WD), but the new lens enables us to work at very short WD at accelerating voltage of 15kV. As a result the spherical (Cs) and chromatic (Cc) aberration constants are 1.9mm and 1.7mm respectively at a WD of 3mm.In order to get large probe current, we increased emission current and got near the distance between the t ip of emi tter and the pr inciple plane of condenser lens.

Field Emission SEM Equipped With Noise Compensator

1973 ◽  
Vol 31 ◽  
pp. 302-303
Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Contrast ◽  
Probe Current ◽  
High Resolution Images ◽  
Scanning Electron

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.

A Simple Transmission Stage for a Scanning Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 134-135
Author(s):  
P. S. D. Lin ◽  
M. K. Lamvik
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Electron Emission ◽  
Objective Lens ◽  
Scattered Electron ◽  
Electron Detector ◽  
Backscattered Electron ◽  
Transmission Stage ◽  
Scanning Electron

Unlike a CEM or high resolution STEM, where the specimen is immersed between the pole pieces of the objective lens, a scanning electron microscope has its specimen stage situated off the lens field. After scattering with the specimen, electrons follow straight paths. It is rather simple to deduce the information from the signal. A transmission stage in a SEM is therefore a useful device for studying various scattering processes and the contrast thus generated.The transmission stage can also be used in connection with the investigation of secondary and backscattered electron emission phenomena. Previously, a back-scattered electron detector was installed in one of the scanning microscopes in the laboratory.

Low-temperature Scanning Electron Microscope constructed with high-excitation objective lens

1989 ◽  
Vol 47 ◽  
pp. 734-735
Author(s):  
H. Koike ◽  
T. Inoué
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Low Temperature ◽  
Scanning Electron Microscope ◽  
Freeze Substitution ◽  
Objective Lens ◽  
Rapid Freezing ◽  
High Excitation ◽  
Temperature Scanning ◽  
Scanning Electron

Low temperature microscope technology can be traced back to the last century including the time of light microscope, and its history is over a hundred years. In the field of electron microscopy, low temperature techniques such as the freeze-fracture replica, freeze-sectioning, freeze-substitution, etc. were tested up to early 1960s. According to the progress of the rapid-freezing method, the freeze-substitution and freeze-etching replica methods have provided great successful results.The low temperature scanning electron microscope (LTSEM) was also tested by Echlin et al. in 1970, and thereafter, a number of LTSEM constructions were attempted. These LTSEMs are generally classified into two groups: the type with fracturing and coating facilities directly attached to the SEM column, and the group having a separated preparation chamber and a transfer device. The LTSEM so far constructed were reviewed comprehensively in greater detail. Some such instruments were designed taking account of stringent requirements of low temperature techniques. These systems, however, seemed to be too comprehensive, involving complex procedures as compared withe their resolutions. In comparison with the conspicuous results obtained by other low temperature techniques, the LTSEM can be regarded as still in the stage prior to practical application from the viewpoint of the high resolution. In consideration of these circumstances, the present paper aims at providing a new LTSEM to realize simple operation retaining the advantage of the ultrastructural preservation by the rapid-freezing and the high resolution by introducing the high-excitation objective lens.

A Micromanipulator for Use in the Column of a Scanning Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 372-373
Author(s):  
James B. Pawley
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Secondary Electron ◽  
Surface Hardness ◽  
Micro Scale ◽  
Macroscopic Object ◽  
Secondary Electron Mode ◽  
Electron Mode ◽  
Scanning Electron

Used in the secondary electron mode, the Scanning Electron Microscope (SEM) produces an image of the outside surface of a microscopic sample which looks very similar to what one might expect to see if the sample was a diffusely illuminated macroscopic object viewed with the unaided eye. Part of the familiarity of such an image is associated with the fact that one seems to look at the sample rather than through it, as in the case with the conventional electron microscope or the high resolution light microscope. A resulting limitation is the fact that an object of interest cannot be observed if it is below the outer surface. It has been shown (Gane and Bowden 1968) that useful surface hardness information can be obtained on a micro scale by observing the deformation produced when a small stylus, attached to a D'Arsonval meter movement, is brought to bear on the surface of a sample while it is in the SEM.

Contrast Effects in High Resolution, Low Voltage SEM

1974 ◽  
Vol 32 ◽  
pp. 452-453
Author(s):  
L. M. Welter
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Voltage ◽  
Electron Source ◽  
Scanning Microscopy ◽  
Contrast Effects ◽  
Probe Current ◽  
Scanning Electron

A scanning electron microscope using a field emission electron source and a single electromagnetic lens can produce a resolution of less than 180Å using an accelerating voltage of only 900v. High resolution, low voltage (0.1-2kV) scanning microscopy offers a number of advantages over the use of higher accelerating voltages. Specimen damage may be reduced because the power (P≃IV) which must be absorbed by the specimen for operation at a given probe current (I) is decreased in proportion to the reduction in accelerating voltage (V).

Electron-optical design of a high-resolution objective lens for low-voltage Scanning Electron Microscope of biological applications

1992 ◽  
Vol 50 (2) ◽  
pp. 950-951
Author(s):  
J. Ximen ◽  
P. S. D. Lin ◽  
J. B. Pawley ◽  
M. Schippert
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Surface Characterization ◽  
Low Voltage ◽  
Optical Design ◽  
Objective Lens ◽  
Magnetic Lens ◽  
Voltage Scanning ◽  
Scanning Electron

By providing higher image contrast and reduced charging artifacts, the low voltage scanning electron microscope (LVSEM) is a valuable tool for surface characterization, of particular importance on nonconductive material such as biological specimens. Several SEM designs optimized for use at low voltage have been proposed.Recently, we have designed a new high resolution LVSEM using a field emission gun. The key problem is to decrease both the spherical and chromatic aberration coefficients by using a magnetic lens of small bore diameters(5mm and 10mm) and a narrow gap (7.5mm) (FIG. 1). In our first design, the magnetic lens is built around the side-entry stage of a Philips 300kV TEM and performs as well as that in the present Hitachi SEM H-900 or H-900S. Its simple design has been chosen for reliability and flexibility in farbrication.

A Miniature Low Voltage SEM with High Resolution

1999 ◽  
Vol 5 (S2) ◽  
pp. 322-323
Author(s):  
J.M. Krans ◽  
T.L. van Rooy
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Low Voltage ◽  
Optical Systems ◽  
Objective Lens ◽  
Secondary Electrons ◽  
Voltage Imaging ◽  
Resolution Imaging ◽  
Scanning Electron

Miniaturization of electron optical systems has gained much interest over the last decade [1,2]. In a scanning electron microscope, downscaling of the column dimensions is expected to allow for high resolution imaging at low electron beam voltage. Main advantages of low voltage imaging are lower penetration depth, increased secondary electron yield, less specimen charging and better topographic contrast [3].We have developed a miniature scanning electron microscope (SEM) with high resolution at low beam energies. The outer dimensions of the miniaturized SEM column are 25 mm diameter and 95 mm length, including conventional field emitter electron source module. The column prototype is shown in Fig. 1. The size reduction has been achieved by the exclusive implementation of electrostatic column components. Electron optical simulations indicate that the retarding objective lens of the miniature SEM allows for a probe resolution of 3 nm at 1 keV beam energy. The secondary electrons are collected at an internal scintillator detector.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

Resolution of a Transmitted Electron Image Formed by A Scanning Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 386-387
Author(s):  
S. Takashima ◽  
H. Hashimoto ◽  
S. Kimoto
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Probe Diameter ◽  
Transmission Electron ◽  
Electron Image ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

The resolution of a conventional transmission electron microscope (TEM) deteriorates as the specimen thickness increases, because chromatic aberration of the objective lens is caused by the energy loss of electrons). In the case of a scanning electron microscope (SEM), chromatic aberration does not exist as the restrictive factor for the resolution of the transmitted electron image, for the SEM has no imageforming lens. It is not sure, however, that the equal resolution to the probe diameter can be obtained in the case of a thick specimen. To study the relation between the specimen thickness and the resolution of the trans-mitted electron image obtained by the SEM, the following experiment was carried out.

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