Annular Focused Electron/Ion Beams for Combining High Spatial Resolution with High Probe Current

2016 ◽  
Vol 22 (5) ◽  
pp. 948-954 ◽  
Author(s):  
Anjam Khursheed ◽  
Wei Kean Ang
Keyword(s):  
Electron Beam ◽  
Ion Beam ◽  
Current Mode ◽  
Spot Size ◽  
Beam Current ◽  
Ion Beams ◽  
Second Order ◽  
Primary Beam ◽  
Objective Lens ◽  
Probe Current

AbstractThis paper presents a proposal for reducing the final probe size of focused electron/ion beam columns that are operated in a high primary beam current mode where relatively large final apertures are used, typically required in applications such as electron beam lithography, focused ion beams, and electron beam spectroscopy. An annular aperture together with a lens corrector unit is used to replace the conventional final hole-aperture, creating an annular ring-shaped primary beam. The corrector unit is designed to eliminate the first- and second-order geometric aberrations of the objective lens, and for the same probe current, the final geometric aberration limited spot size is predicted to be around a factor of 50 times smaller than that of the corresponding conventional hole-aperture beam. Direct ray tracing simulation is used to illustrate how a three-stage core lens corrector can be used to eliminate the first- and second-order geometric aberrations of an electric Einzel objective lens.

scholarly journals Ion beam profiling from the interaction with a freestanding 2D layer

2017 ◽  
Vol 8 ◽  
pp. 682-687 ◽  
Author(s):  
Ivan Shorubalko ◽  
Kyoungjun Choi ◽  
Michael Stiefel ◽  
Hyung Gyu Park
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Beam Current ◽  
Exposure Dose ◽  
Ion Beams ◽  
Gaussian Profile ◽  
Helium Ion ◽  
Spread Function ◽  
Sputtering Yields ◽  
Pattern Resolution

Recent years have seen a great potential of the focused ion beam (FIB) technology for the nanometer-scale patterning of a freestanding two-dimensional (2D) layer. Experimentally determined sputtering yields of the perforation process can be quantitatively explained using the binary collision theory. The main peculiarity of the interaction between the ion beams and the suspended 2D material lies in the absence of collision cascades, featured by no interaction volume. Thus, the patterning resolution is directly set by the beam diameters. Here, we demonstrate pattern resolution beyond the beam size and precise profiling of the focused ion beams. We find out that FIB exposure time of individual pixels can influence the resultant pore diameter. In return, the pore dimension as a function of the exposure dose brings out the ion beam profiles. Using this method of determining an ion-beam point spread function, we verify a Gaussian profile of focused gallium ion beams. Graphene sputtering yield is extracted from the normalization of the measured Gaussian profiles, given a total beam current. Interestingly, profiling of unbeknown helium ion beams in this way results in asymmetry of the profile. Even triangular beam shapes are observed at certain helium FIB conditions, possibly attributable to the trimer nature of the beam source. Our method of profiling ion beams with 2D-layer perforation provides more information on ion beam profiles than the conventional sharp-edge scan method does.

Improvement of ion beam brightness by reducing voltage ripple of an electrostatic accelerator for microbeam focusing by a triplet quadrupole lens system having large spherical aberration coefficient

2013 ◽  
Vol 23 (03n04) ◽  
pp. 171-181 ◽  
Author(s):  
S. Matsuyama ◽  
K. Watanabe ◽  
K. Ishii ◽  
A. Terakawa ◽  
M. Fujisawa ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Spherical Aberration ◽  
Ion Beam ◽  
Spot Size ◽  
Beam Current ◽  
Lens System ◽  
Beam Spot ◽  
Beam Spot Size ◽  
Voltage Ripple ◽  
Terminal Voltage

The microbeam system at Tohoku University was upgraded to a triplet lens system aiming at applying to the analysis of sub-micron features. The triplet lens system has a higher demagnification than the existing doublet system. However, the introduction of the triplet system also resulted in larger chromatic and spherical aberration coefficients. To overcome these problems, the energy resolution of the accelerator was improved by developing a terminal voltage stabilization system. The energy resolution of the accelerator was improved to 1 × 10−5 ΔE/E, which resulted in an increase in the brightness of the beam. The beam brightness was 2.3 pA Δ μm−2 Δ mrad−2 Δ MeV− and was higher in the central region. The effects of the increased chromatic and spherical aberration were mitigated by restricting the divergence angle without reducing the beam current. A beam spot size of 0.6 × 0.8 μm2 was obtained with a beam current of 150 pA.

scholarly journals Beam generations of three kinds of charged particles

1991 ◽  
Vol 9 (1) ◽  
pp. 149-165 ◽  
Author(s):  
K. Niu ◽  
P. Mulser ◽  
L. Drska
Keyword(s):  
Electromagnetic Field ◽  
Electron Beam ◽  
Electromagnetic Waves ◽  
Laser Light ◽  
Ion Beam ◽  
Charged Particles ◽  
Leading Edge ◽  
Heavy Ion ◽  
Ion Beams ◽  
Damping Force

Analyses are given for beam generations of three kinds of charged particles: electrons, light ions, and heavy ions. The electron beam oscillates in a dense plasma irradiated by a strong laser light. When the frequency of laser light is high and its intensity is large, the acceleration of oscillating electrons becomes large and the electrons radiate electromagnetic waves. As the reaction, the electrons feel a damping force, whose effect on oscillating electron motion is investigated first. Second, the electron beam induces the strong electromagnetic field by its self-induced electric current density when the electron number density is high. The induced electric field reduces the oscillation motion and deforms the beam.In the case of a light ion beam, the electrostatic field, induced by the beam charge, as well as the electromagnetic field, induced by the beam current, affects the beam motion. The total energy of the magnetic field surrounding the beam is rather small in comparison with its kinetic energy.In the case of heavy ion beams the beam charge at the leading edge is much smaller in comparison with the case of light ion beams when the heavy ion beam propagates in the background plasma. Thus, the induced electrostatic and electromagnetic fields do not much affect the beam propagation.

Treаtment of аluminа сerаmiсs by intense eleсtrоn аnd iоn beаms

2021 ◽  
Vol 102 (2) ◽  
pp. 50-55
Author(s):  
S.А. Ghyngаzоv ◽  
◽  
V.А. Kоstenkо ◽  
S.V. Matrenin ◽  
A.I. Kupchishin ◽  
...  
Keyword(s):  
Electron Beam Irradiation ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Beams ◽  
Ceramic Surface ◽  
Carbon Ions ◽  
Alumina Ceramics ◽  
Beam Irradiation ◽  
Surface Layers

The paper investigated modification of the microstructure of the surface layers of alumina ceramics under exposure to electron and ion beams. Electron beam irradiation was performed at accelerating voltage U = 15 kV and beam current of J = 70 A and J = 100 A. Ion irradiation was performed with carbon ions at accelerating voltage of U = 180 keV. The current density and energy density varied in the range of 15–85 A/cm2 and 0.3–1.5 J/cm2 , respectively. The amount of energy acting on the ceramic surface depended on the number of pulses N. It is shown that exposure to electron and ion beams changes the microstructure of the irradiated ceramic layer. In general, the effect of exposure is similar for electron and ion irradiation, and it is characterized not only by surface melting, but also by formation of a finer microstructure through the depth of the irradiated layer, which is oriented in the direction of the electron and ion beam exposure. It is shown that crystallization processes in overheated layers of ceramics depend on its type and melting point.

Magnesium Diboride Superconducting Films Synthesized by Different Electron-Beam Annealing Currents

2014 ◽  
Vol 887-888 ◽  
pp. 737-742
Author(s):  
Zhuang Xu ◽  
Xiang Dong Kong ◽  
Jun Wang ◽  
Han Li ◽  
Qian Dai ◽  
...  
Keyword(s):  
Electron Beam ◽  
Magnesium Diboride ◽  
Influence Factors ◽  
Spot Size ◽  
Beam Current ◽  
Annealing Duration ◽  
Zero Field ◽  
Beam Spot ◽  
Beam Spot Size ◽  
Beam Currents

Considerable progress to synthesize magnesium diboride (MgB2) films by electron-beam annealing has been made. A series of MgB2 films with a Tc higher than 35 K had been fabricated. MgB2 film superconductivity is affected by electron-beam accelerating voltage, beam current, annealing duration, beam spot size and Mg/B ratio. In order to fabricate better MgB2 films, these influence factors must be intensively studied. In this paper, the influence of e-beam current on superconductivity was investigated with an accelerating voltage of 32 kV, an annealing time of 0.26 s and different annealing beam currents of 9.9 mA, 10.7 mA, 12.8 mA, 13.3 mA and 14.0 mA. The results show the MgB2 film with 12.8 mA has the highest Tc and the densest structure. Its zero-field Jc at 15K has reached 3.2×106 A/cm2. The variation of the film superconducting properties with the beam currents was grasped, which will lay the foundation for the fabrication of high quality MgB2 thin films

Super-ion-beam accelerator for the ignition of thermonuclear reactions

1980 ◽  
Vol 24 (1) ◽  
pp. 1-14 ◽  
Author(s):  
F. Winterberg
Keyword(s):  
Magnetic Field ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Beams ◽  
Beam Power ◽  
Thermonuclear Reactions ◽  
Beam Voltage ◽  
Multi Stage ◽  
Light Ions ◽  
Thermonuclear Target

A pulsed, multi-stage, high-voltage accelerator is proposed which should be capable of producing intense ion beams of many million amperes and many million volts. Super ion beams produced by this type of accelerator can exceed the limiting Aifvén current for light ions, typically 107 A, at which beam pinching occurs. The beam pinching of these super-beams permits them to be precisely focused onto a thermonuclear target. With such an accelerator it seems to be possible to reach a beam voltage of 108 V with a beam current of 107 A. The resulting beam power of 1015 W should be more than sufficient to ignite a DT thermonuclear microexplosion. By the formation of a stable ion beam superpinch within a thermonuclear target, such a large beam power in conjunction with the strong self-magnetic field of the beam may even lead to the ignition of the DD and perhaps HB11 thermonuclear reactions.

Electron and Focused Ion Beams in Thermal Science and Engineering

2008 ◽  
Author(s):  
Tae-Youl Choi ◽  
Dimos Poulikakos
Keyword(s):  
Electron Beam ◽  
Heavy Ions ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Energy ◽  
Ion Beams ◽  
Focused Ion Beams ◽  
Deposition Method ◽  
Science And Engineering ◽  
Nanoscale Structures

Focused-ion-beam (FIB) is a useful tool for defining nanoscale structures. High energy heavy ions inherently exhibit destructive nature. A less destructive tool has been devised by using electron beam. FIB is mainly considered as an etching tool, while electron beam can be used for deposition purpose. In this paper, both etching and deposition method are demonstrated for applications in thermal science. Thermal conductivity of nanostructures (such as carbon nanotubes) was measured by using the FIB (and electron beam) nanolithography technique. Boiling characteristics was studied in a submicron heater that could be fabricated by using FIB.

Quantitative EDS analysis in the environmental ESEM using a bremstrahlung intensity-based correction for primary electron beam variation and scatter

1996 ◽  
Vol 54 ◽  
pp. 842-843 ◽  
Author(s):  
B.J. Griffin ◽  
C.E. Nockolds
Keyword(s):  
Electron Beam ◽  
Beam Current ◽  
Primary Electron ◽  
Primary Beam ◽  
Minimum Condition ◽  
Chamber Pressure ◽  
Primary Electron Beam ◽  
Faraday Cage ◽  
X Ray ◽  
Eds Analysis

Quantitative EDS analysis of bulk samples in the scanning electron microscope (SEM) or electron microprobe requires, as a fundamental parameter, a stable and reproducible primary electron beam current Beam current is usually measured with a Faraday cage positioned in the electron column below the objective aperture or in the specimen holder. Reproducibility and stability within 1%/hour is a minimum condition.Primary beam current measurement in the ESEM or any high pressure SEM is difficult to measure. Electron-gas interaction in the biased chamber generates a positive ion flow highly amplified relative to the primary beam (Danilatos, 1990) and generates an x-ray signal from the gas. The latter signal amplitude is dependent on primary beam current, chamber pressure and backscatter electron signal from the specimen (Griffin et al. 1993). These interactions prevent quantification of EDS data standardised to Faraday cage primary beam current measurements or x-ray counts from a reference standard.

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.

High-speed Processing with Reactive Cluster Ion Beams

2004 ◽  
Vol 843 ◽  
Author(s):  
Toshio Seki ◽  
Jiro Matsuo
Keyword(s):  
High Speed ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Beams ◽  
High Rate ◽  
Cluster Ions ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Sputtering Yield ◽  
Reactive Cluster

ABSTRACTCluster ion beam processes can produce high rate sputtering with low damage in comparison with monomer ion beam processes. Especially, it is expected that extreme high rate sputtering can be obtained using reactive cluster ion beams. Reactive cluster ion beams, such as SF6, CF4, CHF3, and CH2F2, were generated and their cluster size distributions were measured using Time-of-Flight (TOF) method. Si substrates were irradiated with the reactive cluster ions at the acceleration energy of 5–65 keV. Each sputtering yield was increased with acceleration energy and was about 1000 times higher than that of Ar monomer ions. The sputtering yield of SF6 cluster ions was about 4600 atoms/ion at 65 keV. With this beam, 12 inches wafers can be etched 0.5 μm per minute at 1 mA of beam current. The TOF measurement showed that the size of SF6 cluster was about 550 molecules and the number of fluorine atoms in a SF6 cluster was about 3300. If the sputtered product was SiF, the yield has to be less than 3300 atoms/ion. These results indicate that the reactive cluster ions etch targets not only chemically, but also physically. This high-speed processing with reactive cluster ion beam can be applied to fabricate nano-devices.

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