Electron trajectories in electrostatic fields

1992 ◽  
Vol 50 (2) ◽  
pp. 954-955
Author(s):  
Zbigniew Czyzewski ◽  
David C. Joy
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Magnetic Fields ◽  
Laplace Equation ◽  
Secondary Electron ◽  
Low Voltage ◽  
Electron Trajectories ◽  
Electrostatic Fields ◽  
Image Position ◽  
Detector Placement

Electron microscope use an electron beam to obtain various kind of information about specimen. The electron beam is focussed by electrostatic and magnetic fields and electron detectors employ electrostatic fields to attract or deflect electrons. In many cases the demand to calculate the electron trajectories in a fast and visual way is very strong. One of the most important questions is the problem of the secondary electron (SE) trajectories inside the SEM chamber and the effect of sample charging on detector yield. This is especially important in the low voltage SEM when investigating an uncoated, non-conductive specimen. A relatively large number of calculated trajectories gives a possibility to optimize SE detector placement as well as detector bias.The main problem is solving the Laplace equation in a 3-D space. In the 3-D space composed of cubic cells of dimension Δ3, the Laplace equation takes the following form:

Spreadsheet program for calculating secondary electron trajectories in electrostatic fields

1991 ◽  
Vol 49 ◽  
pp. 534-535
Author(s):  
Grady F. Bradley ◽  
David C. Joy
Keyword(s):  
Secondary Electron ◽  
Low Voltage ◽  
Microsoft Excel ◽  
Secondary Electrons ◽  
Spreadsheet Program ◽  
Electron Trajectories ◽  
Electrostatic Fields ◽  
Effective Use ◽  
Primary Electrons ◽  
Voltage Scanning

With the increasing importance of Low Voltage Scanning Electron Microscopy, the problem of describing the influence exerted by Secondary electron detectors on the path of primary electrons as well as its effects on the trajectories followed by secondary electrons become increasingly important. In situations where uncoated, insulating specimens are studied in an SEM, the additional problem of sample charging also has to be considered. Characterizing these interactions can be very difficult by conventional programming methods. The large number of points and the interdependence of the potentials at all of the points make the “bookkeeping” very difficult to manage. Spreadsheet programs with macroinstruction languages, however, can make these calculations much easier to perform. Not only can spreadsheets be used to calculate the potential field within a microscope column, macro programming can be used to calculate trajectories throughout that field. For the computations described in this paper, Microsoft Excel for the Macintosh was the spreadsheet chosen because of its effective use of the graphics capabilities of the Macintosh.

Residual Gas Reactions in the Electron Microscope: I. Qualitative Observations on the Water Gas Reaction

1968 ◽  
Vol 26 ◽  
pp. 292-293
Author(s):  
Richard E. Hartman ◽  
Roberta S. Hartman ◽  
Peter L. Ramos
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Gas Phase ◽  
Absolute Temperature ◽  
Residual Gas ◽  
Gas Reactions ◽  
Image Position ◽  
The Right ◽  
Water Gas ◽  
Thinning Rate

The action of water and the electron beam on organic specimens in the electron microscope results in the removal of oxidizable material (primarily hydrogen and carbon) by reactions similar to the water gas reaction .which has the form:The energy required to force the reaction to the right is supplied by the interaction of the electron beam with the specimen.The mass of water striking the specimen is given by:where u = gH2O/cm2 sec, PH2O = partial pressure of water in Torr, & T = absolute temperature of the gas phase. If it is assumed that mass is removed from the specimen by a reaction approximated by (1) and that the specimen is uniformly thinned by the reaction, then the thinning rate in A/ min iswhere x = thickness of the specimen in A, t = time in minutes, & E = efficiency (the fraction of the water striking the specimen which reacts with it).

Linewidth measurement using the low voltage SEM

1986 ◽  
Vol 44 ◽  
pp. 652-653
Author(s):  
M.G. Rosenfield
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Secondary Electron ◽  
Low Voltage ◽  
Fabrication Process ◽  
Critical Dimensions ◽  
Linewidth Measurement ◽  
Threshold Technique ◽  
Scanning Electron

Minimum feature sizes in experimental integrated circuits are approaching 0.5 μm and below. During the fabrication process it is usually necessary to be able to non-destructively measure the critical dimensions in resist and after the various process steps. This can be accomplished using the low voltage SEM. Submicron linewidth measurement is typically done by manually measuring the SEM micrographs. Since it is desirable to make as many measurements as possible in the shortest period of time, it is important that this technique be automated.Linewidth measurement using the scanning electron microscope is not well understood. The basic intent is to measure the size of a structure from the secondary electron signal generated by that structure. Thus, it is important to understand how the actual dimension of the line being measured relates to the secondary electron signal. Since different features generate different signals, the same method of relating linewidth to signal cannot be used. For example, the peak to peak method may be used to accurately measure the linewidth of an isolated resist line; but, a threshold technique may be required for an isolated space in resist.

scholarly journals ANALYZING THE EFFECT OF MICRO RUBBER, MICRO SIO2, AND NANO SIO2 IN MICROCRACKS IN SELF-CONSOLIDATING CONCRETE (SEM OBSERVATION)

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Ehsan Adili ◽  
Moein Riginejad
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Secondary Electron ◽  
Point Of View ◽  
The Other ◽  
Self Consolidating Concrete ◽  
Nano Sio2 ◽  
Rubber Waste ◽  
Scanning Electron

The present study is an attempt to analyze the effect of micro rubber waste in self- consolidating concrete (SCC) and to compare the concrete containing SCC with conventional additives such as micro SiO2 and nano SiO2. The use of rubber waste can be substantially important from the environmental point of view. Hence, concrete specimens containing 1, 3 and 5% micro rubber waste were made. Moreover, specimens containing 1, 3 and 5% nano SiO2 and 4, 8 and 12% micro SiO2 were prepared to compare their behaviour and microstructure with each other and with the witness specimens. The effect of the other parameters such as the specimen age and the w/c ratio on the microstructure of concrete containing rubber waste was also studied. Thereafter, the specimens were imaged using a scanning electron microscope (SEM) to observe and compare the microcracks in the concrete and secondary electron beam (SE) was used to obtain their images. The results of the microstructural consideration of different specimens showed that 1% of micro rubber waste can improve the behaviour of self-consolidating concrete, but the concrete microstructure strength and quality decline with an increase in its amount.

Studies of poorly conducting samples by the low-loss electron method in the SEM

1994 ◽  
Vol 52 ◽  
pp. 1022-1023
Author(s):  
O. C. Wells ◽  
S. A. Rishton
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Beam Energy ◽  
Secondary Electron ◽  
Imaging Method ◽  
Tungsten Filament ◽  
Low Loss ◽  
Information Depth ◽  
Charging Current ◽  
Scanning Electron

The low-loss electron (LLE) image in the scanning electron microscope (SEM) shows stronger topographic contrast, less sensitivity to specimen charging and a shallower information depth in comparison with the more familiar secondary electron (SE) imaging method. When working with a poorly conducting or insulating sample the beam energy must be reduced to typically ~1.5 keV to minimise the net charging current at the surface of the specimen. Even if this is done correctly the topographic contrasts in the LLE image can still be considerably stronger than in the SE image.Fig. 1(a) shows the original LLE detector in which the sample is inclined at 45° to the electron beam. Fig. 1(b) shows a new detector which operates with a specimen tilt of 20°. Both have been used in a Cambridge Instrument Co. S250 Mk.III SEM.The possibility of obtaining a LLE image with a 20° specimen tilt is demonstrated with uncoated photoresist in Fig. 2 (tungsten filament) and with a “Crystal“ image store to capture and replay the image.

From the Scanning Electron Microscope to the Scanning Electron Macroscope with X-Ray Microanalysis in the ESEM

2000 ◽  
Vol 6 (S2) ◽  
pp. 792-793 ◽  
Author(s):  
Raynald Gauvin
Keyword(s):  
Monte Carlo ◽  
Electron Beam ◽  
Electron Microscope ◽  
Incident Beam ◽  
Correction Procedure ◽  
Measured Intensity ◽  
X Ray ◽  
Image Position ◽  
Corrected Intensity ◽  
Scanning Electron

Recently, a new correction procedure has been proposed in order to perform X-Ray microanalysis in the ESEM or in the VP-SEM1. This new correction procedure is based on this equation:where I is the measured intensity at a given pressure P, Ip is the intensity that would be generated without any gas in the microscope (the corrected intensity) and Im is the intensity with complete scattering of the electron beam. Im is therefore the contribution of the skirt on I. In equation (1), fp is the fraction of the incident beam, which is not scattered by the gas above the specimen, and it can be obtained from Monte Carlo simulations or from an analytical equation.

scholarly journals New perspectives on nano-engineering by secondary electron spectroscopy in the helium ion and scanning electron microscope

2018 ◽  
Vol 8 (02) ◽  
pp. 226-240 ◽  
Author(s):  
Nicola Stehling ◽  
Robert Masters ◽  
Yangbo Zhou ◽  
Robert O'Connell ◽  
Chris Holland ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Spectroscopy ◽  
Secondary Electron ◽  
Helium Ion ◽  
Image Position ◽  
Scanning Electron

Abstract

Quality of the Secondary Electron Image at Low Accelerating Voltage

1970 ◽  
Vol 28 ◽  
pp. 390-391
Author(s):  
T. Kosuge ◽  
H. Hashimoto ◽  
M. Sato ◽  
S. Kimoto
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Image Quality ◽  
Electron Probe ◽  
Secondary Electron ◽  
Secondary Electron Image ◽  
Electron Image ◽  
Image Detail ◽  
Scanning Electron

A scanning electron microscope is usually operated at the accelerating voltage of 25 kV or so. The use of a lower accelerating voltage has many advantages to improve the image quality, such as presentation of fine details of the specimen surface, the prevention of the charge-up and that of the damage to the specimen by electron beam bombardment. In this paper, the quality of the secondary electron image is discussed under various accelerating voltages between 1 and 25 kV.As far it is considered that the limit of the resolution of a secondary electron image is only depend on the diameter of the incident electron probe, the higher accelerating voltage is prefered. Attainable resolutions in this experiment for various voltages are shown in Figure 1. However, as shown in Figure 2 most of the secondary electron images in which a critical resolution is not necessary reveal fine image detail with better contrast at lower voltages.

In Situ Observation of Electron Beam-Induced Phase Transformation of CaCO3 to CaO via ELNES at Low Electron Beam Energies

2014 ◽  
Vol 20 (3) ◽  
pp. 715-722 ◽  
Author(s):  
Ute Golla-Schindler ◽  
Gerd Benner ◽  
Alexander Orchowski ◽  
Ute Kaiser
Keyword(s):  
Phase Transformation ◽  
Electron Beam ◽  
Electron Microscope ◽  
Bond Length ◽  
Transmission Electron Microscope ◽  
Low Voltage ◽  
In Situ Observation ◽  
Edge Structure ◽  
Transmission Electron

AbstractIt is demonstrated that energy-filtered transmission electron microscope enables following of in situ changes of the Ca-L2,3 edge which can originate from variations in both local symmetry and bond lengths. Low accelerating voltages of 20 and 40 kV slow down radiation damage effects and enable study of the start and finish of phase transformations. We observed electron beam-induced phase transformation of single crystalline calcite (CaCO3) to polycrystalline calcium oxide (CaO) which occurs in different stages. The coordination of Ca in calcite is close to an octahedral one streched along the <111> direction. Changes during phase transformation to an octahedral coordination of Ca in CaO go along with a bond length increase by 5 pm, where oxygen is preserved as a binding partner. Electron loss near-edge structure of the Ca-L2,3 edge show four separated peaks, which all shift toward lower energies during phase transformation at the same time the energy level splitting increases. We suggest that these changes can be mainly addressed to the change of the bond length on the order of picometers. An important pre-condition for such studies is stability of the energy drift in the range of meV over at least 1 h, which is achieved with the sub-Ångström low-voltage transmission electron microscope I prototype microscope.

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