A controller for safe, convenient operation of LaB6 emitters on electron-beam instruments

Author(s):  
W. J. Abramson ◽  
H. W. Estry ◽  
L. F. Allard

LaB6 emitters are becoming increasingly popular as direct replacements for tungsten filaments in the electron guns of modern electron-beam instruments. These emitters offer order of magnitude increases in beam brightness, and, with appropriate care in operation, a corresponding increase in source lifetime. They are, however, an order of magnitude more expensive, and may be easily damaged (by improper vacuum conditions and thermal shock) during saturation/desaturation operations. These operations typically require several minutes of an operator's attention, which becomes tedious and subject to error, particularly since the emitter must be cooled during sample exchanges to minimize damage from random vacuum excursions. We have designed a control system for LaBg emitters which relieves the operator of the necessity for manually controlling the emitter power, minimizes the danger of accidental improper operation, and makes the use of these emitters routine on multi-user instruments.Figure 1 is a block schematic of the main components of the control system, and Figure 2 shows the control box.

Author(s):  
Wei-Chih Wang ◽  
Jian-Shing Luo

Abstract In this paper, we revealed p+/n-well and n+/p-well junction characteristic changes caused by electron beam (EB) irradiation. Most importantly, we found a device contact side junction characteristic is relatively sensitive to EB irradiation than its whole device characteristic; an order of magnitude excess current appears at low forward bias region after 1kV EB acceleration voltage irradiation (Vacc). Furthermore, these changes were well interpreted by our Monte Carlo simulation results, the Shockley-Read Hall (SRH) model and the Generation-Recombination (G-R) center trap theory. In addition, four essential examining items were suggested and proposed for EB irradiation damage origins investigation and evaluation. Finally, by taking advantage of the excess current phenomenon, a scanning electron microscope (SEM) passive voltage contrast (PVC) fault localization application at n-FET region was also demonstrated.


Author(s):  
Igor Melnyk ◽  
Sergey Tugay ◽  
Volodymyr Kyryk ◽  
Iryna Shved

The algorithm is considered for calculating the focal distance of a hollow conical electron beam generated by high-voltage glow discharge electron guns with magnetic focusing of the beam in the drift region, as well as a method for calculating the diameter of the focal ring and its thickness for such a beam. The proposed algorithm is based on the theory of electron drift in the field of a focusing magnetic lens and is designed using the methods of discrete mathematics and the minimax analysis. The obtained simulation results made it possible to establish the influence of the magnetic lens current on the focal diameter of a hollow conical electron beam and on its focal ring thickness. It is shown that the change in the focal parameters of a hollow conical electron beam can be effectively provided through the regulation of the magnetic lens current.


Carbon ◽  
1969 ◽  
Vol 7 (6) ◽  
pp. 732
Author(s):  
R.D Reiswig ◽  
P.E Armstrong ◽  
L.S Levinson

2009 ◽  
Vol 4 (1) ◽  
pp. 30-36
Author(s):  
Petr Bak ◽  
Dmitriy Bolkhovityanov ◽  
Andrey Korepanov ◽  
Pavel Logatchev ◽  
Dmitriy Malyutin ◽  
...  

Instrument for bunch tilt measurements in linear collider is presented. Electron beam probe basic principles are described and method of bunch tilt measurements is discussed. The simulation results of testing beam interaction with tilted relativistic bunch are presented. Main components of the bunch tilt measurement error are determined.


2002 ◽  
Vol 760 ◽  
Author(s):  
Colin Inglefield ◽  
Royce Anthon

ABSTRACTAn instructional laboratory in two-dimensional diffraction is discussed. The experiment is appropriate for undergraduate students in materials science, solid-state physics (as was the case with our group), modern physics, or optics. The experiment is performed using visible light from a laser incident on a 2D lattice of gold dots deposited with electron beam lithography on a glass substrate. The pattern is microscopic with a lattice constant on the same order of magnitude as the wavelength of light used. Students observe the diffraction pattern, and then quantitatively determine the positions of maxima. These data are used by the students to reconstruct the (real space) microscopic lattice. The students can simulate the experiment with software that computes reciprocal lattice and diffraction patterns for an arbitrary 2D lattice.


2013 ◽  
Vol 4 ◽  
pp. 919-926 ◽  
Author(s):  
Paul M Weirich ◽  
Marcel Winhold ◽  
Christian H Schwalb ◽  
Michael Huth

We present the application of an evolutionary genetic algorithm for the in situ optimization of nanostructures that are prepared by focused electron-beam-induced deposition (FEBID). It allows us to tune the properties of the deposits towards the highest conductivity by using the time gradient of the measured in situ rate of change of conductance as the fitness parameter for the algorithm. The effectiveness of the procedure is presented for the precursor W(CO)6 as well as for post-treatment of Pt–C deposits, which were obtained by the dissociation of MeCpPt(Me)3. For W(CO)6-based structures an increase of conductivity by one order of magnitude can be achieved, whereas the effect for MeCpPt(Me)3 is largely suppressed. The presented technique can be applied to all beam-induced deposition processes and has great potential for a further optimization or tuning of parameters for nanostructures that are prepared by FEBID or related techniques.


1995 ◽  
Vol 406 ◽  
Author(s):  
G. E. Philippa ◽  
J. A. Mejia Galeana ◽  
C. Cassou ◽  
P. D. Wang ◽  
C. Guasch ◽  
...  

AbstractThe fabrication of GaAs-GaAIAs coupled quantum dots and of quantum rings using electron beam lithography and dry etching is described. Coupled dots of physical diameter of 500 and 250 nm were fabricated and processed with top electrical contacts to apply an electric field. We show that the emission spectrum of coupled dots is modified by the electric field. Quantum rings of 400 nm outer diameter and wall thickness of 25 nm were fabricated. The emission spectrum from rings showed the quantum well emission shifted to higher energies and although its intensity decreased by about one order of magnitude there was little linewidth broadening.


1985 ◽  
Vol 54 ◽  
Author(s):  
S. Ingrey ◽  
J.P.D. Cook

A dual ion gun system has been proposed (D.E. Sykes et al, Appl. Surf. Sci. 5(1980)103) to reduce texturing and improve depth resolution during Auger sputter depth profiling. We have evaluated this ion gun configuration by profiling a variety of multilayer structures. With careful alignment of the guns, we have obtained a dramatic decrease in ion-induced texturing often seen when a single ion gun is used. This effect was particularly pronounced for polycrystalline Al films on Si where an order of magnitude improvement in depth resolution was achieved. Further refinements of the technique include the use of low energy (IkeV) grazing incidence xenon ions and a small electron beam probe area. Depth profiles obtained from Ni/Cr, W/Si, and GaAs/GaAlAs multilayer structures will also be discussed.


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