Development of 100 kV Field Emission Scanning Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 408-409
Author(s):  
H. Koike ◽  
Y. Harada ◽  
T. Goto ◽  
Y.Kokubo ◽  
K. Yamada ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Chemical Elements ◽  
Signal To Noise Ratio ◽  
Electron Gun ◽  
The Past ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Scanning Electron

During the past ten years, the resolution of the CTEM has been improved to a theoretical value determined by spherical and diffraction aberrations. In the scanning electron microscope, however, the resolution is restricted by the signal-to-noise ratio. Crewe et al were the first to increase the resolution by applying a field emission source to a 35 kV scanning electron microscope, resulting in a 5 Å resolution. Owing to its prominent brightness, the feild emission electron gun promises to increase not only the resolution of STEM images, but also to realize an analytical electron microscope which identifies chemical elements, crystalline structures and chemical bonding in specimen microareas in the order of less than 100 Å.

X-ray detection performance of a 300KV field-emission Analytical Electron Microscope

1993 ◽  
Vol 51 ◽  
pp. 250-251
Author(s):  
C. E. Lyman ◽  
J. I. Goldstein ◽  
D.B. Williams ◽  
D.W. Ackland ◽  
S. von Harrach ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Detection Performance ◽  
Electron Gun ◽  
X Rays ◽  
X Ray ◽  
Analytical Electron ◽  
Analytical Electron Microscope

A major goal of analytical electron micrsocopy (AEM) is to detect small amounts of an element in a given matrix at high spatial resolution. While there is a tradeoff between low detection limit and high spatial resolution, a field emission electron gun allows detection of small amounts of an element at sub-lOnm spatial resolution. The minimum mass fraction of one element measured in another is proportional to [(P/B)·P]-1/2 where the peak-to-background ratio P/B and the peak intensity P both must be high to detect the smallest amount of an element. Thus, the x-ray detection performance of an analytical electron microscope may be characterized in terms of standardized measurements of peak-to-background, x-ray intensity, the level of spurious x-rays (hole count), and x-ray detector performance in terms of energy resolution and peak shape.This paper provides measurements of these parameters from Lehigh’s VG Microscopes HB-603 field emission AEM. This AEM was designed to provide the best x-ray detection possible.

Development of a 300 kV field emission TEM

1993 ◽  
Vol 51 ◽  
pp. 1080-1081
Author(s):  
Y. Ishida ◽  
Y. Bando ◽  
Y. Kitami ◽  
T. Tomita ◽  
M. Kersker
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Atomic Layer ◽  
Electron Gun ◽  
Emission Current ◽  
Long Period ◽  
Current Variation ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Ultrahigh Sensitivity

The 300 kV analytical electron microscope, as compared with the 100 to 200 kV instruments, have excellent features such as the high resolution of TEM images, high P/B ratio of EDS and PEELS, and high spacial resolution in analysis.We hereby report the principal specifications of an ultrahigh sensitivity and ultrahigh resolution field emission type electron microscope, which, capable of giving full play to the above-mentioned features of the 300 kV analytical instrument, allows elemental analysis at the single atomic layer level (nm regions).Its electron gun, simply operated by CPU control, allows emission current to be obtained at the touch of a single button. As the emitter, a W (100)-TF emitter, which can be used simply, stably, and for a long period of time, is employed. After build-up, this emitter can obtain about 10 times the angular current density of the W (310) emitter. Around the emitter are provided three electrodes to make emission current variation and electrostatic lens function independent of each other.

A Compact Field Emission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 32-33 ◽  
Author(s):  
L. M. Welter ◽  
V. J. Coates
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Electron Gun ◽  
Readout System ◽  
Amplitude Control ◽  
Emission Electron ◽  
Compact Field ◽  
New Instrument ◽  
Scanning Electron

A compact field emission scanning electron microscope has been developed and modeled after the optical microscope. The new instrument consists of the field emission electron gun, an externally adjustable aperture strip containing four different hole sizes, an electromagnetic single deflection system, an electromagnetic stigmator with independent magnitude and amplitude control, an ion pumped specimen chamber, and a television readout system. No magnetic lenses are used.The field emission electron gun incorporates an electrode system which simultaneously accelerates and focuses the electrons drawn from a field emission source. Several improvements have been made in the basic gun to provide for higher tip stability and reliability. A unique pumping scheme has been incorporated in the gun to provide tip region pressures in the order of 10-9 Torr and below so that stable field emission can be routinely obtained.

Microprocessor control of a field-emission scanning electron microscope (Model S-800)

1983 ◽  
Vol 41 ◽  
pp. 410-411
Author(s):  
S. Saito ◽  
Y. Nakaizumi ◽  
T. Nagatani ◽  
H. Todokoro
Keyword(s):  
Electron Microscope ◽  
Control System ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Operating Conditions ◽  
Gun Control ◽  
Electron Gun ◽  
Microprocessor Control ◽  
Emission Electron ◽  
Scanning Electron

We have developed an ultra high resolution scanning electron mícroscope utílízíng a fíeld emíssíon electron source (Fig.1). This instrument has a guaranteed resolution of 2 nm in the secondary electron image mode and it has incorporated a microprocessor control for optimized operating conditions and maximum ease of operation by various automated functions. The microprocessor control system includes field emission electron gun control, electron optical system control, and video signal control. The field emission electron gun control system includes flashing operation which is used to clean the tip surface by heating for a very short time, high voltage operation of accelerating voltage (V0) and tip voltage (V1), correction of emission current which changes with time, and correction of virtual source position which changes with a voltage ratio V0/V1. We have automated these series of operations by developing an auto FE gun control system. Fig. 2 shows details of this system.

Low Acceleration Scanning Electron Microscope

1980 ◽  
Vol 38 ◽  
pp. 70-71
Author(s):  
H. Todokoro ◽  
S. Fukuhara ◽  
Y. Sakitani
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Secondary Electron Emission ◽  
High Sensitivity ◽  
Electron Gun ◽  
High Yield ◽  
List Type ◽  
Acceleration Voltage ◽  
Scanning Electron

A low acceleration scanning electron microscope ( LASEM ) offers several advantages: no charging effects low radiation damage high yield for secondary electron emission high sensitivity for surface topography The application of a low acceleration microscope, however, has been limited to special purposes because of its poor resolution. A high resolution LASEM has been developed and is shown in Fig.1. The microscope uses a new electron gun with a field emission cathode. The gun 1,000 times brighter than a conventional thermionic cathode. The relation between brightness and resolution of a SEM for 1 kV acceleration voltage is shown in Fig.2. The three regions in the figure correspond to tungsten thermionic, LaB6 thermionic and field emission guns. Resolution is approximately 1 μm in the case of the tungsten thermionic gun at 1 kV, while resolution is 200 A in the new microscope equipped with a field emission gun.

A Field Emission Scanning Electron Microscope Operating in the Secondary Electron Imaging Mode

1972 ◽  
Vol 30 ◽  
pp. 434-435
Author(s):  
T. Komoda ◽  
S. Saito ◽  
Y. Kakinuma ◽  
A. Okura
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Secondary Electron ◽  
Electron Gun ◽  
Emission Current ◽  
Electron Imaging Mode ◽  
Imaging Mode ◽  
Electron Imaging ◽  
Scanning Electron

The authors have built a surface scanning electron microscope incorporating a field emission electron gun. The gun has a brightness almost three order of magnitude higher than that of the ordinary thermionic electron gun, which is promissing high resolution in the secondary electron imaging mode.Emission current fluctuation, which is one of the most serious problems in field emission guns, depends on the vacuum condition around the field emission tip. In order to provide a good vacuum environment, the gun assembly in this microscope is located in the center of an ion-pump system which is symmetrically laid out relative to the electron optical axis. Two tips are mounted on a turret holder and they are exchangeable from the outside without disturbing the vacuum in the gun chamber. A stable emission current of the order of 10μA is obtainable at the normal vacuum operation better than 5x10-10 Torr.

An Electron Gun Scanning Microscope

1968 ◽  
Vol 26 ◽  
pp. 360-361
Author(s):  
A. V. Crewe ◽  
D. Johnson ◽  
M. Isaacson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Beam Current ◽  
Angular Spread ◽  
Electron Gun ◽  
Emission Current ◽  
Scanning Microscope ◽  
Schematic Drawing ◽  
Scanning Electron

A simple scanning electron microscope has been built using a field emission electron gun. The gun is used alone, without the aid of auxiliary lenses, and is theoretically capable of producing a 100 Å probe with a beam current of 10-10 A. Such a beam current allows scan times of the order of a few seconds.A schematic drawing of the microscope is shown in Fig. 2. The field emission voltage is applied to the first anode which controls the emission current. An accelerating voltage is applied to the second anode, and the field between the anodes focuses the electrons to form an image of the tip at the specimen. The angular spread of the beam is limited by an aperture on the second anode.

Development and applications of an analytical electron microscope with a field emission electron gun

1990 ◽  
Vol 25 (4) ◽  
pp. 375-395 ◽  
Author(s):  
A. Koreeda ◽  
T. Ishibashi ◽  
K. Shimizu ◽  
M. Tomita ◽  
C. Kimura ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Electron Gun ◽  
Emission Electron ◽  
Analytical Electron ◽  
Analytical Electron Microscope

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.

High-Resolution, Low-Voltage SEM of Cell Wall Regeneration of Yeast Shizosaccharomyces Pombe Protoplasts

1988 ◽  
Vol 46 ◽  
pp. 208-211
Author(s):  
M. Osumi ◽  
N. Yamada ◽  
T. Nagatani
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Low Voltage ◽  
Cell Wall Regeneration ◽  
The Past ◽  
The Poor ◽  
Probe Size ◽  
Beam Damage ◽  
Biological Field ◽  
Scanning Electron

Even though many early workers had suggested the use of lower voltages to increase topographic contrast and to reduce specimen charging and beam damage, we did not usually operate in the conventional scanning electron microscope at low voltage because of the poor resolution, especially of bioligical specimens. However, the development of the “in-lens” field emission scanning electron microscope (FESEM) has led to marked inprovement in resolution, especially in the range of 1-5 kV, within the past year. The probe size has been cumulated to be 0.7nm in diameter at 30kV and about 3nm at 1kV. We have been trying to develop techniques to use this in-lens FESEM at low voltage (LVSEM) for direct observation of totally uncoated biological specimens and have developed the LVSEM method for the biological field.

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