The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Ilona Mullerova - One of the best experts on this subject based on the ideXlab platform.
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simulations and measurements in Scanning Electron Microscopes at low Electron energy
Scanning, 2016Co-Authors: C G H Walker, Luděk Frank, Ilona MullerovaAbstract:Summary The advent of new imaging technologies in Scanning Electron Microscopy (SEM) using low energy (0–2 keV) Electrons has brought about new ways to study materials at the nanoscale. It also brings new challenges in terms of understanding Electron transport at these energies. In addition, reduction in energy has brought new contrast mechanisms producing images that are sometimes difficult to interpret. This is increasing the push for simulation tools, in particular for low impact energies of Electrons. The use of Monte Carlo calculations to simulate the transport of Electrons in materials has been undertaken by many authors for several decades. However, inaccuracies associated with the Monte Carlo technique start to grow as the energy is reduced. This is not simply associated with inaccuracies in the knowledge of the scattering cross-sections, but is fundamental to the Monte Carlo technique itself. This is because effects due to the wave nature of the Electron and the energy band structure of the target above the vacuum energy level become important and these are properties which are difficult to handle using the Monte Carlo method. In this review we briefly describe the new techniques of Scanning low energy Electron microscopy and then outline the problems and challenges of trying to understand and quantify the signals that are obtained. The effects of charging and spin polarised measurement are also briefly explored. Scanning 9999:1–17, 2016. © 2016 Wiley Periodicals, Inc.
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collection of secondary Electrons in Scanning Electron Microscopes
Journal of Microscopy, 2009Co-Authors: Ilona Mullerova, Ivo KonvalinaAbstract:Collection of the secondary Electrons in the Scanning Electron microscope was simulated and the results have been experimentally verified for two types of the objective lens and three detection systems. The aberration coefficients of both objective lenses as well as maximum axial magnetic fields in the specimen region are presented. Compared are a standard side-attached secondary Electron detector, in which only weak electrostatic and nearly no magnetic field influence the signal trajectories in the specimen vicinity, and the side-attached (lower) and upper detectors in an immersion system with weak electrostatic but strong magnetic field penetrating towards the specimen. The collection efficiency was calculated for all three detection systems and several working distances. The ability of detectors to attract secondary Electron trajectories for various initial azimuthal and polar angles was calculated, too. According to expectations, the lower detector of an immersion system collects no secondary Electrons I and II emitted from the specimen and only backscattered Electrons and secondary Electrons III form the final image. The upper detector of the immersion system exhibits nearly 100% collection efficiency decreasing, however, with the working distance, but the topographical contrast is regrettably suppressed in its image. The collection efficiency of the standard detector is low for short working distances but increases with the same, preserving strong topographical contrast.
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imaging of specimens at optimized low and very low energies in Scanning Electron Microscopes
Scanning, 2006Co-Authors: Ilona MullerovaAbstract:The modern trend towards low Electron energies in Scanning Electron microscopy (SEM), characterised by lowering the acceleration voltages in low-voltage SEM (LVSEM) or by utilising a retarding-field optical element in low-energy SEM (LESEM), makes the energy range where new contrasts appear accessible. This range is further extended by a Scanning low-energy Electron microscope (SLEEM) fitted with a cathode lens that achieves nearly constant spatial resolution throughout the energy scale. This enables one to optimise freely the Electron beam energy according to the given task. At low energies, there exist classes of image contrast that make particular specimen data visible most effectively or even exclusively within certain energy intervals or at certain energy values. Some contrasts are well understood and can presently be utilised for practical surface examinations, but others have not yet been reliably explained and therefore supplementary experiments are needed.
P. A. Todua - One of the best experts on this subject based on the ideXlab platform.
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calibration of Scanning Electron Microscopes over a wide range of magnifications
Measurement Techniques, 2017Co-Authors: R V Kirtaev, P. A. Todua, Yu A Kuzin, V B Mityukhlyaev, M N Filippov, V G MaslovAbstract:A new method is proposed for calibrating Scanning Electron Microscopes (SEM) with magnification in the 10–50000× range using an end gauge and an auxiliary structure. Use of a certified end gauge ensures traceability of the calibration results to the primary standard for the meter. The relative expanded uncertainty of measurements on an S-4800 SEM at magnifications of 1000, 10000, and 50000× is less than 0.14%.
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Calibration stability of Scanning Electron Microscopes
Measurement Techniques, 2013Co-Authors: A V Zablotskii, V. V. Al’zoba, S. A. Morozov, P. A. ToduaAbstract:The medium-term storage stability and reproducibility defined in the course of calibration of the scale factor of Scanning Electron Microscopes are established with the use of an MShPS-2.0K measure. Conclusions are drawn to the effect that the dependence of the scale factor on the working distance may lead to some scatter of the measurement results and that direct comparison of the dimensions of the measured subject and a reference object obtained with the same parameters of the microscope is required to increase the measurement accuracy.
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classification of test objects for use in calibration of Scanning Electron Microscopes in the nanometric range
Measurement Techniques, 2009Co-Authors: Yu. A. Novikov, A. V. Rakov, P. A. ToduaAbstract:A classification of test objects for use in calibration of Scanning Electron Microscopes in the nanometric range is created. The shape of the relief profile of the elements of the test objects and the relationship of the profile to the physical mechanisms underlying the formation of the signal generated by a microscope functioning in a mode for the collection of secondary slow Electrons is used as the basis of the classification.
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Measurement of linear dimensions of pattern elements of micro- and nano-structures under high- and low-voltage Scanning Electron Microscopes
Measurement Techniques, 2009Co-Authors: Ch. P. Volk, Yu. A. Novikov, A. V. Rakov, P. A. ToduaAbstract:Measurements of the line width of one and the same test object under high- and low-voltage Scanning Electron Microscopes are performed.
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Accuracy in linear dimensions measurement in Scanning Electron Microscopes in microtechnology and nanotechnology
Measurement Techniques, 2008Co-Authors: Yu. A. Novikov, A. V. Rakov, P. A. ToduaAbstract:A study has been made on the effects of Scanning Electron microscope parameters on the accuracy in measuring the linear dimensions in microtechnology and nanotechnology. Definitions are given of the errors with which these parameters should be known for using such Microscopes in such technologies.
Anjam Khursheed - One of the best experts on this subject based on the ideXlab platform.
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a high resolution add on in lens attachment for Scanning Electron Microscopes
Scanning, 2006Co-Authors: Anjam Khursheed, N Karuppiah, S H KohAbstract:A compact add-on objective lens for the Scanning Electron microscope (SEM) has been designed and tested. The lens is < 35 mm high and can be fitted on to the specimen stage as an easy-to-use attachment. Initial results show that it typically improves the spatial resolution of the SEM by a factor of three. The add-on unit is based upon a permanent magnet immersion lens design. Apart from the extra attachment to the specimen stage, the SEM with the add-on lens functions in the normal way. The in-lens unit can comfortably accommodate specimen heights up to 10 mm. The new add-on lens unit opens up the possibility of operating existing SEMs in the high-resolution in-lens mode. By using a deflector at the top of the add-on lens unit, it can also operate as a quantitative multichannel voltage contrast spectrometer, capable of recording the energy spectrum of the emitted secondary Electrons. Initial experiments confirm that a significant amount of voltage contrast can be obtained.
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a method of dynamic chromatic aberration correction in low voltage Scanning Electron Microscopes
Ultramicroscopy, 2005Co-Authors: Anjam KhursheedAbstract:A time-of-flight concept that dynamically corrects for chromatic aberration effects in Scanning Electron Microscopes (SEMs) is presented. The method is predicted to reduce the microscope's chromatic aberration by an order of magnitude. The scheme should significantly improve the spatial resolution of low-voltage Scanning Electron Microscopes (LVSEMs). The dynamic means of correcting for chromatic aberration also allows for the possibility of obtaining high image resolution from Electron guns that have relatively large energy spreads.
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a high resolution mixed field immersion lens attachment for conventional Scanning Electron Microscopes
Review of Scientific Instruments, 2002Co-Authors: Anjam Khursheed, N KaruppiahAbstract:This article deals with a compact mixed field add-on lens attachment for conventional Scanning Electron Microscopes (SEMs). By immersing the specimen in a mixed electric–magnetic field combination, the add-on lens is able to provide high image resolution at relatively low landing energies (<1 keV). Experimental results show that the add-on lens unit enables a tungsten gun SEM to acquire images with a resolution of better than 4 nm at a landing energy of 600 eV, which lies close to simulation predictions. Normally, this type of SEM would only be able to provide this kind of resolution at high voltages (30 kV).
P. S. D. Lin - One of the best experts on this subject based on the ideXlab platform.
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Theoretical calculation of probe size of low‐voltage Scanning Electron Microscopes
Journal of Microscopy, 1993Co-Authors: J. Ximen, Z. Shao, P. S. D. LinAbstract:Summary Detailed investigating into the effects of spherical and chromatic aberrations, diffraction and the probe current allows the more general formulae for the optimized aperture and the minimum probe radius in low-voltage Scanning Electron Microscopes (LVSEMs) to be derived using both wave optics and geometric optics. The probe sizes for a diversity of Electron sources in LVSEMs have been estimated, which may be useful for practical applications. The computed results indicate the possibility of achieving 1·5–2·0-nm resolution at low voltages.
Yu. A. Novikov - One of the best experts on this subject based on the ideXlab platform.
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A virtual Scanning Electron microscope. 3. A semiempirical model of the SEM signal generation
Russian Microelectronics, 2014Co-Authors: Yu. A. NovikovAbstract:Experiments are analyzed on Scanning Electron Microscopes (SEMs) with test objects having a trapezoidal profile and large tilt angles of the side walls. Based on the analysis, a semiempirical generation model of images in a SEM, operating in the low-voltage mode and high-voltage mode during recording back-scattered and secondary slow Electrons (SSEs), is proposed. The model is intended for application in a virtual SEM (VSEM).
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Operation of an Electronic lithograph in the mode of a Scanning Electron microscope
Russian Microelectronics, 2012Co-Authors: V. A. Kal’nov, Yu. A. Novikov, A. A. OrlikovskyAbstract:The operation of the Raith-150 Electronic lithograph in the mode of a Scanning Electron microscope is examined. Sizes of the pixel and effective diameter of an Electron probe are determined along both Scanning directions. The parameters of a system for Scanning and forming the lithograph’s Electron probe compare well with those of the best Scanning Electron Microscopes.
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classification of test objects for use in calibration of Scanning Electron Microscopes in the nanometric range
Measurement Techniques, 2009Co-Authors: Yu. A. Novikov, A. V. Rakov, P. A. ToduaAbstract:A classification of test objects for use in calibration of Scanning Electron Microscopes in the nanometric range is created. The shape of the relief profile of the elements of the test objects and the relationship of the profile to the physical mechanisms underlying the formation of the signal generated by a microscope functioning in a mode for the collection of secondary slow Electrons is used as the basis of the classification.
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Measurement of linear dimensions of pattern elements of micro- and nano-structures under high- and low-voltage Scanning Electron Microscopes
Measurement Techniques, 2009Co-Authors: Ch. P. Volk, Yu. A. Novikov, A. V. Rakov, P. A. ToduaAbstract:Measurements of the line width of one and the same test object under high- and low-voltage Scanning Electron Microscopes are performed.
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Accuracy in linear dimensions measurement in Scanning Electron Microscopes in microtechnology and nanotechnology
Measurement Techniques, 2008Co-Authors: Yu. A. Novikov, A. V. Rakov, P. A. ToduaAbstract:A study has been made on the effects of Scanning Electron microscope parameters on the accuracy in measuring the linear dimensions in microtechnology and nanotechnology. Definitions are given of the errors with which these parameters should be known for using such Microscopes in such technologies.
