Characterization of the Interface in a TiC Reinforced Ti-6%A1-4%V Composite Using Monte Carlo Simulations and FEGSEM.

1997 ◽  
Vol 3 (S2) ◽  
pp. 527-528
Author(s):  
Raynald Gauvin ◽  
Priti Wanjara ◽  
Robin A.L. Drew ◽  
Steve Yue
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Metallic Matrix ◽  
Weight Ratio ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Small Probe ◽  
Low Energy Electrons

Metal matrix composite (MMC) materials are promising materials because of their higher specific mechanical properties (e.g. strength-to-weight ratio) relative to conventional metallic alloys. However, during the processing of these materials, the development of an interfacial reaction zone between the reinforcing material (generally a ceramic) and the metallic matrix may occur, which typically degrades the mechanical properties of these materials if not controlled. Since these interfaces are generally quite small (from 5 to 500 nm), Transmission Electron Microscopy (TEM) is the technique of choice for characterization because of its outstanding spatial resolution. However, specimen preparation for TEM (e.g. ion milling) is quite difficult for MMC materials, due to the combination of two completely different material types, specifically a hard and brittle reinforcement phase incorporated in a relatively soft metallic matrix. Also, since there is only a small amount of the material which is transparent to electrons after specimen preparation, TEM as a materials characterization technique suffers from a lack of statistical robustness, which is a serious drawback.To characterize materials with a spatial resolution close to that of TEM, low voltage field emission scanning electron microscopy is an option because of the small interaction volume of low energy electrons, as well as the small probe size of these microscopes (typically < 5 nm).

Transmission Electron Microscopy of Semiconductor Based Products

1998 ◽  
Vol 523 ◽  
Author(s):  
John Mardinly ◽  
David W. Susnitzky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Beam ◽  
Semiconductor Industry ◽  
Size Reduction ◽  
Specimen Preparation ◽  
Specimen Thickness ◽  
Ion Milling ◽  
Feature Size ◽  
Transmission Electron

AbstractThe demand for increasingly higher performance semiconductor products has stimulated the semiconductor industry to respond by producing devices with increasingly complex circuitry, more transistors in less space, more layers of metal, dielectric and interconnects, more interfaces, and a manufacturing process with nearly 1,000 steps. As all device features are shrunk in the quest for higher performance, the role of Transmission Electron Microscopy as a characterization tool takes on a continually increasing importance over older, lower-resolution characterization tools, such as SEM. The Ångstrom scale imaging resolution and nanometer scale chemical analysis and diffraction resolution provided by modem TEM's are particularly well suited for solving materials problems encountered during research, development, production engineering, reliability testing, and failure analysis. A critical enabling technology for the application of TEM to semiconductor based products as the feature size shrinks below a quarter micron is advances in specimen preparation. The traditional 1,000Å thick specimen will be unsatisfactory in a growing number of applications. It can be shown using a simple geometrical model, that the thickness of TEM specimens must shrink as the square root of the feature size reduction. Moreover, the center-targeting of these specimens must improve so that the centertargeting error shrinks linearly with the feature size reduction. To meet these challenges, control of the specimen preparation process will require a new generation of polishing and ion milling tools that make use of high resolution imaging to control the ion milling process. In addition, as the TEM specimen thickness shrinks, the thickness of surface amorphization produced must also be reduced. Gallium focused ion beam systems can produce hundreds of Ångstroms of amorphised surface silicon, an amount which can consume an entire thin specimen. This limitation to FIB milling requires a method of removal of amorphised material that leaves no artifact in the remaining material.

On Low Voltage Scanning Electron Microscopy and Chemical Microanalysis

2000 ◽  
Vol 6 (4) ◽  
pp. 307-316 ◽  
Author(s):  
E.D. Boyes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Energy Dispersive ◽  
Beam Specimen ◽  
Topographic Analysis ◽  
X Ray ◽  
Voltage Scanning ◽  
Scanning Electron

AbstractThe current status and general applicability of scanning electron microscopy (SEM) at low voltages is reviewed for both imaging (low voltage scanning electron microscopy, LVSEM) and chemical microanalysis (low voltage energy-dispersive X-ray spectrometry, LVEDX). With improved instrument performance low beam energies continue to have the expected advantages for the secondary electron imaging of low atomic number (Z) and electrically non-conducting samples. They also provide general improvements in the veracity of surface topographic analysis with conducting samples of all Z and at both low and high magnifications. In new experiments the backscattered electron (BSE) signal retains monotonic Z dependence to low voltages (<1 kV). This is contrary to long standing results in the prior literature and opens up fast chemical mapping with low dose and very high (nm-scale) spatial resolution. Similarly, energy-dispersive X-ray chemical microanalysis of bulk samples is extended to submicron, and in some cases to <0.1 μm, spatial resolution in three dimensions at voltages <5 kV. In favorable cases, such as the analysis of carbon overlayers at 1.5 kV, the thickness sensitivity for surface layers is extended to <2 nm, but the integrity of the sample surface is then of concern. At low beam energies (E0) the penetration range into the sample, and hence the X-ray escape path length out of it, is systematically restricted (R = F(E05/3)), with advantages for the accuracy or elimination of complex analysis-by-analysis matrix corrections for absorption (A) and fluorescence (F). The Z terms become more sensitive to E0 but they require only one-time calibrations for each element. The new approach is to make the physics of the beam–specimen interactions the primary factor and to design enabling instrumentation accordingly.

Pre-Meeting Topical Conference

2002 ◽  
Vol 8 (I1) ◽  
pp. 20-20
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Voltage ◽  
Ion Beam ◽  
Analytical Electron Microscopy ◽  
Polymeric Materials ◽  
Specimen Preparation ◽  
Microbeam Analysis ◽  
Scanning Electron

Topic: Characterization of Non-Conductive or Charging Materials by Microbeam AnalysisThe goal of this topical conference is to present the state of the art for materials characterization of non-conductive or charging materials using microbeam analysis. Examples of charging materials include polymeric materials, ceramic materials, and photoresist materials in the microelectronic industry. Also, the characterization of biological specimens will be covered because they are prone to problems related to charging. These materials are of great technological importance and their characterization is still a great challenge because they charge when analyzed with an electron beam. The techniques of microbeam analysis that will be considered are: X-ray Microanalysis in the Electron Microprobe, Low Voltage Scanning Electron Microscopy, Environmental Scanning Electron Microscopy, Analytical Electron Microscopy with Field Emission Transmission Electron Microscopy, and Focused Ion Beam Milling for specimen preparation. World experts will present papers on these topics. Papers from this topical conference will be published in a special issue of Microscopy & Microanalysis.

On Low Voltage Scanning Electron Microscopy and Chemical Microanalysis

2000 ◽  
Vol 6 (4) ◽  
pp. 307-316
Author(s):  
E.D. Boyes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Energy Dispersive ◽  
Beam Specimen ◽  
Topographic Analysis ◽  
X Ray ◽  
Voltage Scanning ◽  
Scanning Electron

Abstract The current status and general applicability of scanning electron microscopy (SEM) at low voltages is reviewed for both imaging (low voltage scanning electron microscopy, LVSEM) and chemical microanalysis (low voltage energy-dispersive X-ray spectrometry, LVEDX). With improved instrument performance low beam energies continue to have the expected advantages for the secondary electron imaging of low atomic number (Z) and electrically non-conducting samples. They also provide general improvements in the veracity of surface topographic analysis with conducting samples of all Z and at both low and high magnifications. In new experiments the backscattered electron (BSE) signal retains monotonic Z dependence to low voltages (<1 kV). This is contrary to long standing results in the prior literature and opens up fast chemical mapping with low dose and very high (nm-scale) spatial resolution. Similarly, energy-dispersive X-ray chemical microanalysis of bulk samples is extended to submicron, and in some cases to <0.1 μm, spatial resolution in three dimensions at voltages <5 kV. In favorable cases, such as the analysis of carbon overlayers at 1.5 kV, the thickness sensitivity for surface layers is extended to <2 nm, but the integrity of the sample surface is then of concern. At low beam energies (E0) the penetration range into the sample, and hence the X-ray escape path length out of it, is systematically restricted (R = F(E05/3)), with advantages for the accuracy or elimination of complex analysis-by-analysis matrix corrections for absorption (A) and fluorescence (F). The Z terms become more sensitive to E0 but they require only one-time calibrations for each element. The new approach is to make the physics of the beam–specimen interactions the primary factor and to design enabling instrumentation accordingly.

scholarly journals Process for obtaining synthetic foam with aluminum matrix Al-5052 by method of tixoinfiltration

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Joao Roberto Sartori Moreno ◽  
Rafael Claudiano de Moraes ◽  
Joao Paulo de Oliveira Paschoal ◽  
Rodrigo Henrique Lopes
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Syntactic Foam ◽  
Metallic Matrix ◽  
Aluminum Matrix ◽  
Acoustic Properties ◽  
Energy Dispersive ◽  
Metallic Foams ◽  
Compression Tests ◽  
X Ray

The metallic foams have lower density, and important physical, mechanical, thermal and acoustic properties, has been highlighted in its use in innovative technologies. As a subgroup of the class of metallic foams, the syntactic metallic foams which consists of the addition of hollow ceramic balloons in a metallic matrix in aluminum Al-5052 by process of tixoinfiltration. The microstructure was studied by optical and electron microscopy extended by energy-dispersive X-ray spectrometry, while the basic mechanical properties were mapped by standardized compression tests. Therefore, a syntactic foam design was developed in this work, where we obtained a 30% reduction in density and a reasonable increase in hardness due to the homogeneous dispersion of the ceramic balloons

Ultra-high-vacuum, high-resolution Transmission Electron Microscopy at 400 kV

1986 ◽  
Vol 44 ◽  
pp. 606-609
Author(s):  
F. A. Ponce ◽  
S. Suzuki ◽  
H. Kobayashi ◽  
Y. Ishibashi ◽  
Y. Ishida ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Vacuum ◽  
Milling Process ◽  
Electron Bombardment ◽  
Ultra High Vacuum ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Transmission Electron ◽  
Preparation Stage ◽  
Resolution Imaging

Electron microscopy in an ultra high vacuum (UHV) environment is a very desirable capability for the study of surfaces and for near-atomic-resolution imaging. The existence of amorphous layers on the surface of the sample generally prevents the direct observation of the free surface structure and limits the degree of resolution in the transmission electron microscope (TEM). In conventional TEM, these amorphous layers are often of organic nature originating from the electron bombardment of hydrocarbons in the vicinity of the sample. They can in part also be contaminants which develop during the specimen preparation and transport stages. In the specimen preparation stage, contamination can occur due to backsputtering during the ion milling process. In addition, oxide layers develop from contact to air during transport to the TEM. In order to avoid these amorphous overlayers it is necessary: i) to improve the vacuum of the instrument, thus the need for ultra high vacuum; and ii) to be able to clean the sample and transfer it to the column of the instrument without breaking the vacuum around the sample.

Low-Voltage, High-Resolution, Scanning Electron Microscopy of Platelet-Bound Fibrinogen

1996 ◽  
Vol 54 ◽  
pp. 316-317
Author(s):  
S.R. Simmons ◽  
R.M. Albrecht
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Low Voltage ◽  
Blood Clot ◽  
Light And Electron Microscopy ◽  
Essential Element ◽  
Specimen Preparation ◽  
Platelet Surface ◽  
Fibrinogen Binding ◽  
Adhesive Interactions

An essential element in blood clot formation is fibrinogen-mediated platelet aggregation. Fibrinogen is an adhesive plasma protein which binds to the αIIbp3 integrin on activated platelet surfaces. Platelets do not aggregate in the absence of fibrinogen binding, and fibrinogen bound to surfaces of platelets in aggregates is localized to regions of platelet-platelet contact. The fibrinogen molecule is symmetrical and bifunctional and may directly bridge the gap between platelets to bind to receptors on two adjacent platelets. However, the precise mechanism by which fibrinogen links platelets is unclear.Previously we have utilized colloidal gold labeling with correlative light and electron microscopy to investigate the binding of fibrinogen to receptors on surfaces of spread, substrate adherent platelets. The initial binding of gold-conjugated fibrinogen (FgnAu) and subsequent ligand-triggered receptor movement was followed on living platelets by video-enhanced light microscopy. Fibrinogen receptors initially are dispersed over much of the platelet surface and move centripetally upon fibrinogen binding, ultimately forming a band of bound fibrinogen on the platelet surface overlying a densely woven band of actin filaments surrounding the central granulomere. After preparation for electron microscopy, the same platelets as were followed in the light microscope were located in the high voltage TEM and the low voltage, high resolution, SEM (Hitachi S-900) and the final locations of the gold labeled receptor/ligand complexes were determined relative to internal or surface ultrastructure, respectively. More recently, we have utilized the SEM operated at low (1-2 kV) beam voltage to examine in detail the binding of unlabeled fibrinogen to platelets. With appropriate specimen preparation, individual cell surface macromolecules can be resolved in situ by low voltage SEM. In addition to the centripetal receptor redistribution seen with FgnAu, unlabeled fibrinogen appeared to undergo self-adhesive interactions following binding to platelet fibrinogen receptors, forming small, branched and globular protein aggregates during translocation across the platelet surface.(Fig. 1)

Preparation of Electropolished Transverse Sections of Thin Aluminum Sheet for Transmission Electron Microscopy

1987 ◽  
Vol 115 ◽  
Author(s):  
Steve Smith
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transverse Section ◽  
Aluminum Sheet ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Transmission Electron ◽  
Thin Aluminum ◽  
Time Required

ABSTRACTThe preparation of transverse section TEM foils from thin (0.2 mm to 1.5 mm) aluminum sheet would usually be accomplished by a combination of dimpling and ion milling. Both of these techniques are time consuming. A technique has been developed which allows these transverse section foils to be prepared by electropolishing, which greatly reduces the time required for specimen preparation. This technique also produces far more thin area for examination than a comparable foil which has been dimpled and ion milled, and eliminates artifacts produced by ion milling.

Unconventional Specimen Preparation Techniques Using High Resolution Low Voltage Field Emission Scanning Electron Microscopy to Study Cell Motility, Host Cell Invasion, and Internal Cell Structures in Toxoplasma gondii

2002 ◽  
Vol 8 (2) ◽  
pp. 94-103 ◽  
Author(s):  
Heide Schatten ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Host Cell ◽  
Cell Invasion ◽  
Low Voltage ◽  
Cytoskeletal Proteins ◽  
Specimen Preparation ◽  
Host Cell Invasion ◽  
Apicomplexan Parasites ◽  
Preparation Techniques

Apicomplexan parasites employ complex and unconventional mechanisms for cell locomotion, host cell invasion, and cell division that are only poorly understood. While immunofluorescence and conventional transmission electron microscopy have been used to answer questions about the localization of some cytoskeletal proteins and cell organelles, many questions remain unanswered, partly because new methods are needed to study the complex interactions of cytoskeletal proteins and organelles that play a role in cell locomotion, host cell invasion, and cell division. The choice of fixation and preparation methods has proven critical for the analysis of cytoskeletal proteins because of the rapid turnover of actin filaments and the dense spatial organization of the cytoskeleton and its association with the complex membrane system. Here we introduce new methods to study structural aspects of cytoskeletal motility, host cell invasion, and cell division of Toxoplasma gondii, a most suitable laboratory model that is representative of apicomplexan parasites. The novel approach in our experiments is the use of high resolution low voltage field emission scanning electron microscopy (LVFESEM) combined with two new specimen preparation techniques. The first method uses LVFESEM after membrane extraction and stabilization of the cytoskeleton. This method allows viewing of actin filaments which had not been possible with any other method available so far. The second approach of imaging the parasite's ultrastructure and interactions with host cells uses semithick sections (200 nm) that are resin de-embedded (Ris and Malecki, 1993) and imaged with LVFESEM. This method allows analysis of structural detail in the parasite before and after host cell invasion and interactions with the membrane of the parasitophorous vacuole as well as parasite cell division.

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