A high current focused electron ring-beam column design

2019 ◽  
Vol 34 (36) ◽  
pp. 1942002
Author(s):  
Pranesh Balamuniappan ◽  
Wei Kean Ang ◽  
Anjam Khursheed
Keyword(s):  
Electron Beam ◽  
Beam Current ◽  
Accelerator Physics ◽  
Beam Angle ◽  
Third Order ◽  
Beam Columns ◽  
Probe Size ◽  
Spot Radius ◽  
Column Design ◽  
Working Distance

There are many applications in electron microscopy, electron spectroscopy, as well as accelerator physics that require the combination of minimizing a focused electron beam’s probe size while maximizing its beam current. This paper describes how this can be done through the use of annular focused electron beam column designs, where an electron beam is propagated and focused in the form of a ring beam. For probe semi-angles of [Formula: see text] radians, a column consisting of two identical electric sectors and two identical focusing lenses functioning with odd symmetry will be presented, together with a wide-angle cold field emission gun design. The column is designed to cancel energy dispersion while limiting geometric aberrations to the third order at the point of final focus. This design is predicted to have over two orders of magnitude higher beam current than the corresponding conventional on-axis focused electron beam columns for the same final probe size. For a 1.2 keV annular electron beam, simulation results predict a spot radius of 4.8 nm at a working distance of 3.4 mm, final beam angle of [Formula: see text] mrad, and energy spread of [Formula: see text] eV.

The Investigation of Microstructures Fabrication on Quartz Substrate Employing Electron Beam Lithography (EBL) and ICP-RIE Process

2014 ◽  
Vol 980 ◽  
pp. 69-73 ◽  
Author(s):  
Liyana Shamsuddin ◽  
Khairudin Mohamed ◽  
Alsadat Rad Maryam
Keyword(s):  
Electron Beam ◽  
Electron Beam Lithography ◽  
Inductively Coupled Plasma ◽  
Quartz Substrate ◽  
Spot Size ◽  
Beam Current ◽  
Step Size ◽  
Nano Structures ◽  
Wide Range ◽  
Working Distance

The fabrication of micro or nano-structures on quartz substrate has attracted researchers' attention and interests in recent years due to a wide range of potential applications such as NEMS/MEMS, sensors and biomedical engineering. Various types of next generation lithographic methods have been explored since optical lithography physical limitations has hindered the fabrication of high aspects ratio (HAR) structure on quartz substrates. In this research, the top-down fabrication approach was employed to fabricate microstructures on quartz substrate using Electron Beam Lithography (EBL) system, followed by the pattern transfer process using Inductively Coupled Plasma-Reactive Ion Etching (ICP-RIE) technique. The factors that influenced pattern definition include the type of electron beam (e-beam) photoresist, e-beam exposure parameter such as spot size, working distance, write field, step size, e-beam current, dosage as well as the type of developer and its developing time. The optimum conditions were investigated in achieving micro or nano-structures. Field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray (EDX) and atomic force microscope (AFM) were utilized to characterize the structures profiles.

Design of Electrostatic Focusing System for Space Electron Beam Gun

2015 ◽  
Vol 713-715 ◽  
pp. 1364-1368
Author(s):  
De Wang
Keyword(s):  
Electron Beam ◽  
Computer Aided Design ◽  
Beam Current ◽  
Domestic Space ◽  
Electron Beam Current ◽  
Spot Radius ◽  
Single Lens ◽  
Beam Section ◽  
Aided Design ◽  
Parameters Calculation

The developmental situation of space welding technology home and abroad is introduced. Then it’s put forward that the designing scheme and the computer aided design (CAD) method of main focusing system of the domestic space electron beam gun with equal-diameter three-cylinder electrostatic single lens. The parameters calculation of the focusing system is completed through language C utilizing computer programming and a satisfying result is gotten.The result shows that electron beam current disperse focusing is less, and the beam section is less in the deflection magnetic field, the beam spot radius on the workpiece is about 0.6300mm at least, and can meet the requirement of the space welding and cutting.

Probe size and 5th-order aberration

1987 ◽  
Vol 45 ◽  
pp. 134-135 ◽  
Author(s):  
Zhifeng Shao
Keyword(s):  
Electron Probe ◽  
Spherical Aberration ◽  
Wave Length ◽  
Cylindrical Symmetry ◽  
Electron Wave ◽  
Third Order ◽  
The Third ◽  
Probe Radius ◽  
Small Probe ◽  
Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

Practical Importance of Spatial Resolution and Analytical Sensitivity in AEM X-ray Microanalysis

1990 ◽  
Vol 48 (2) ◽  
pp. 432-433
Author(s):  
J. Zhang ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Spatial Resolution ◽  
Practical Importance ◽  
Beam Current ◽  
Specimen Thickness ◽  
Analytical Sensitivity ◽  
Related Factors ◽  
X Ray ◽  
Probe Size ◽  
Excitation Volume ◽  
Two Parameters

Analytical sensitivity and spatial resolution are important and closely related factors in x-ray microanalysis using the AEM. Analytical sensitivity is the ability to distinguish, for a given element under given conditions, between two concentrations that are nearly equal. The analytical sensitivity is directly related to the number of x-ray counts collected and, therefore, to the probe current, specimen thickness and counting time. The spatial resolution in AEM analysis is determined by the probe size and beam broadening in the specimen. A finer probe and a thinner specimen give a higher spatial resolution. However, the resulting lower beam current and smaller X-ray excitation volume degrade analytical sensitivity. A compromise must be made between high spatial resolution and an acceptable analytical sensitivity. In this paper, we show the necessity of evaluating these two parameters in order to determine the low temperature Fe-Ni phase diagram.A Phillips EM400T AEM with an EDAX/TN2000 EDS/MCA system and a VG HB501 FEG STEM with a LINK AN10 EDS/MCA system were used.

Electron behavior in the gaseous environment of the ESEM chamber

1996 ◽  
Vol 54 ◽  
pp. 838-839 ◽  
Author(s):  
S.A. Wight
Keyword(s):  
Secondary Electron ◽  
High Vacuum ◽  
Beam Current ◽  
Chamber Pressure ◽  
Environmental Scanning ◽  
Carbon Block ◽  
Faraday Cup ◽  
X Ray ◽  
Gaseous Environment ◽  
Working Distance

Measurements of electrons striking the sample in the Environmental Scanning Electron Microscope (ESEM) are needed to begin to understand the effect of the presence of the gas on analytical measurements. Accurate beam current is important to x-ray microanalysis and it is typically measured with a faraday cup. A faraday cup (Figure 1) was constructed from a carbon block embedded in non-conductive epoxy with a 45 micrometer bore platinum aperture over the hole. Currents were measured with an electrometer and recorded as instrument parameters were varied.Instrument parameters investigated included working distance, chamber pressure, condenser percentage, and accelerating voltage. The conditions studied were low vacuum with gaseous secondary electron detector (GSED) voltage on; low vacuum with GSED voltage off; and high vacuum (GSED off). The base conditions were 30 kV, 667 Pa (5 Torr) water vapor, 100,000x magnification with the beam centered inside aperture, GSED voltage at 370 VDC, condenser at 50%, and working distance at 19.5 mm. All modifications of instrument parameters were made from these conditions.

Low - Voltage Scanning Electron Microscopy Imaging, Secondary and Backscatter, With Microchannel Plate Detector

1990 ◽  
Vol 48 (1) ◽  
pp. 442-442
Author(s):  
Galen Powers ◽  
Ray Cochran
Keyword(s):  
Low Voltage ◽  
Beam Current ◽  
Microchannel Plate ◽  
Normal Operation ◽  
Microscopy Imaging ◽  
Backscatter Signal ◽  
Vacuum Interface ◽  
Width Measurements ◽  
Working Distance ◽  
Beam Currents

The capability to obtain symmetrical images at voltages as low as 200 eV and beam currents less than 9 pico amps is believed to be advantageous for metrology and study of dielectric or biological samples. Symmetrical images should allow more precise and accurate line width measurements than currently achievable by traditional secondary electron detectors. The low voltage and current capability should allow imaging of samples which traditionally have been difficult because of charging or electron beam damage.The detector system consists of a lens mounted dual anode MicroChannel Plate (MCP) detector, vacuum interface, power supplies, and signal conditioning to interface directly to the video card of the SEM. The detector has been miniaturized so that it does not interfere with normal operation of the SEM sample handling and alternate detector operation. Biasing of the detector collection face will either add secondaries to the backscatter signal or reject secondaries yielding only a backscatter image. The dual anode design allows A−B signal processing to provide topological information as well as symmetrical A+B images.Photomicrographs will show some of the system capabilities. Resolution will be documented with gold on carbon. Variation of voltage, beam current, and working distance on dielectric samples such as glass and photoresist will demonstrate effects of common parameter changes.

Cathodoluminescence of SiO2/Si System

2009 ◽  
Vol 156-158 ◽  
pp. 487-492 ◽  
Author(s):  
M.V. Zamoryanskaya
Keyword(s):  
Activation Energy ◽  
Electron Beam ◽  
Rise Time ◽  
Silicon Oxide ◽  
Beam Current ◽  
Electron Beam Current ◽  
Electron Traps ◽  
Definition Of ◽  
Luminescent Centers

In this paper the new method for determination of luminescent centers concentration are discussed. While the possibility of electron traps determination and definition of its activation energy are suggested. The cathodoluminescent (CL) method was used. The determination of luminescent centers concentration in silicon oxide is based on the measurements of dependences of CL intensity on electron beam current. The presence and energy of activation of electron traps were studied by measurement of rise time and decay of luminescent band during the stationary irradiation of silica by electron beam.

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