bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of STEM-EDX Mapping for Characterizing Microstructural Instabilities En 9-12% Chromium Steels With Martensitic-Austenitic Microstructure
Authors: Klotz U E , Solenthaler C , Uggowitzer P J , Speidel M O
Published: July 2020

Materials for high-temperature application, e.g. in gas-turbine compressor discs or steam turbine rotors, are often susceptible to microstructural instabilities during long-term service. Such instabilities reduce the service life due to a deterioration of the mechanical properties. Therefore, it is most important to identify such instabilities, which often take place in sub-micrometer scale. A class of materials widely used in power generating industries are the martensitic 9-12% Cr steels. In the present work STEM-EDX mappings were used to reveal the distribution of alloying elements in 9-12% Cr steels with a martensitic-austenitic microstructure developed recently.

The chemical composition of the material investigated was Fe-10.1Cr-6.2Co-5.2Mn-2.1Ni-1.2Mo-0.47V-0.1 IN (weight-percent). The material was subjected to a two step heat-treatment of normalizing at 1175°C for 1.5h with subsequent quenching and controlled tempering at 600°C for 20h. Due to the high amount of manganese and nickel a duplex microstructure of 30-40vol.% of austenite in a matrix of tempered martensite is formed during tempering.
Microstructure and Microchemistry of Inconel 600 STEAM Generator Tubing
Authors: Perovic V , Perovic A , Weatherly GC , Brennenstuhl AM
Published: July 2020

Inconel 600 is an austenitic Ni-Cr-Fe alloy which is extensively used for tubing in steam generators of pressurized light water reactors (PWR) and CANDU heavy water reactors, because of its excellent mechanical properties and corrosion resistance. However, there have been instances of intergranular stress corrosion cracking of tubes in operating steam generators. The chemistry and the structure of grain boundaries and grain boundary precipitation have emerged as factors of prime importance in understanding stress corrosion cracking and intergranular attack of nickel-base alloys (see e.g. ref. l).

In this study analytical electron microscopy was used to determine the microstructure of grain boundary and matrix precipitates, grain boundary chromium content and dislocation substructure of selected steam generating tubes of CANDU reactors. The results of the in-service materials are compared with as-received material. Two JEOL 2010 STEM instruments were used in this study.
Observation and Mearsurement of Concentration Moments in Rapid Coarsening, Self-Stressed, Au-Ni Thin Plates
Authors: Hyde B , Reynolds WT
Published: July 2020

The focus of our study is to demonstrate experimentally how elastic stress effects diffusion behavior and coarsening kinetics in a two-phase binary alloy. This work, based on the theory of Cahn and Kobayashi, focuses on elastic stresses in a thin plate. For the case of phase separation with lattice misfit between solute-rich and solute-poor phases, the diffusion of solute distorts the host lattice and causes elastic stress in the matrix. If the plate is sufficiently thin, the stress can cause the plate to buckle. The buckling stress biases the direction of diffusion, which increases the bending stress even further. Thus, the diffusion and the buckling stress are coupled; each affects the other. The interplay between the two is easiest to observe in a solution in which the solute and solvent have high misfit.
Characterization of the Phase Evolution of Mosi2 - TiB2 Composites Produced by In-Situ Reactions Using Scanning Electron Microscopy (SEM), Electron Probe Microanalysis (EPMA), and X-Ray Diffraction (XRD)
Authors: Dempere L A , Kaufman M J
Published: July 2020

Intermetallics are playing an important role in the development of new materials able of sustaining the escalating demands of the aerospace industry. A significant improvement in weight, operating temperatures or mechanical performance is required for materials to be considered as replacements in the most demanding applications. Molybdenum disilicide is one such compound that has potential for high temperature applications. Its most attractive properties are its high melting point (2020°C), reasonable density (6.24 g/cm3), and excellent high temperature oxidation and corrosion resistance. However, low ambient fracture toughness and loss of strength at elevated temperatures have been the most significant limitations to the use of MoSi2 in structural applications.

The more promising solutions for improving the mechanical properties of brittle intermetallics such as MoSi2 are based on the incorporation and control of secondary phases. To date, the artificial introduction of reinforcing phases or their generation via in-situ reactions have been explored.
Copper Oxidation Via “Ex-Situ” TEM
Authors: Kliewer CE , Disko MM , Soled SL , DeMartin G , Baumgartner J , Miseo S
Published: July 2020

The ability to understand and control the microstructure of materials under “real life” conditions is of great interest to both the scientific and industrial communities. In recent years, a variety of “ex-situ” TEM methods have been developed to improve this knowledge base.

ExxonMobil's dedicated reactor system developed for “ex-situ” TEM was used to study the oxidation and reduction of copper on a carbon film and Cu on a Si support. By following the oxidation of specific Cu particles, it was possible to illustrate the oxidation process. A standard, commercially available, 200 mesh Cu grid covered with a holey C support film was used for the Cu on C study. Small Cu islands were vapor deposited from the grid onto the C film during a high temperature reduction in the reactor (Figure 1). The grid was transferred under inert conditions into the TEM where the Cu metal islands were imaged (Figure 2a).
Electron Irradiation Damage in Multi-Component Glasses
Authors: Jiang N , Silcox J
Published: July 2020

Understanding electron beam induced damage in glasses, especially in multi-component glasses, is very important, since the interaction of electron probes with glass is a very common approach to determine glass composition and structure. For example, the decay of characteristic X-ray and Auger electron intensities, using electron beams as probes, of alkalis in glasses have been known for years. In addition, both phase separation and formation of gas bubbles in the glasses have also been reported. Many irradiation effects are strongly dependent on the structure, bonding and composition of matter. In general, three types of mechanisms, knock-on damage, ionization and field-induced migration have been introduced to describe the damage induced by electron irradiation. Here, we demonstrate electron irradiation induced phase decomposition in a multi-component oxide glass, and introduce a modified model to interpret the damage process.
HREM and Image Simulation of Short-Range-Order Domains in Ion Irradiated Zirconolite
Authors: Wang S X , Wang L M , Ewing R C
Published: July 2020

Zirconolite (CaZrTi2O7) is an important phase proposed for immobilization of plutonium. Radiation effects in zirconolite were studied by 1 MeV Kr+ and 1.5 MeV Xe+ irradiation at various temperatures. Zirconolite became amorphous at temperatures below a critical temperature, Tc. The critical temperature was found to be a function of ion species: Tc - 654 K for 1 MeV Kr+ and 710 K for 1.5 MeV Xe+. The temperature dependence of amorphization dose is shown in FIG. 1. Above Tc, the specimen remained crystalline after prolonged irradiation (up to 3.6×l015 ions/cm2). However, the high-temperature irradiated zirconolite was transformed into the fluorite structure (as shown by the strong diffraction maxima in FIG. 2). In addition to the maxima from the fluorite structure, strong diffuse maxima were observed surrounding the Bragg position of pyrochlore superlattice (FIG. 2).
TEM Characterization of Grain Boundary Structure in YBCO Coated Conductors
Authors: Kung H , Hirth JP , Foltyn SR , Arendt PN , Jia QX , Maley MP
Published: July 2020

Studies of defects, such as grain boundaries, in high temperature superconductors (HTS) are important due to the interaction of the defects with flux-bearing vortices. The benefit of in-plane grain alignment has been documented in YBCO thin film bicrystals, in which the high critical current density (Jc) observed across small angle grain boundaries deteriorates exponentially with grain boundary angles beyond ∼ 7°. In addition to the weak coupling effect, a grain boundary may also influence the transport properties via the grain boundary dislocations (GBDs) serving as pinning centers to increase the critical current density. There have been a number of studies on grain boundary structures in YBCO. Despite many differences in structure among the different types of boundaries, it has been established that the low angle [001] tilt boundary in YBCO consists of aperiodic array of edge type GBDs with [100] type Burgers vector that accommodate the lattice mismatch, and the regions between the GBDs are channels of relatively undisturbed lattices [1].
Strained BaTiO3 / SrTiO3 Superlattice Grwon by Reactive Molecular Beam Epitaxy
Authors: Tian W , Jiang J C , Haeni J H , Schlom D G , Pan X Q
Published: July 2020

Due to their unique dielectric and ferroelectric properties, ferroelectric superlattices have attracted increasing interest for fundamental and applied research. Such superlattices with a small layer thickness (a few unit cells) provide a model system to investigate the effects of crystal size, internal strain, interfacial structure and chemistry on physical properties. Recent development in oxide thin film epitaxial growth using reactive molecular beam epitaxy (MBE) make it possible to grow high quality metastable oxide superlattice films. BaTiO3 / SrTiO3 system has been selected for this study.

[(BaTiO3)5 / (SrTiO3)5]20 superlattice films were grown on (001) SrTiO3 substrates by reactive MBE. The atomic structure of these films and the related heterostructural interfaces have been investigated by a combination of high-resolution transmission electron microscopy (HRTEM) and computer image simulations. HRTEM studies were conducted within JEOL-4000EX electron microscope equipped with Gatan Image Filter (GIF), which is operated at 400 kV.
Atomic Structure of La067Ca0.33MnO3 Thin Films on LaAlO3
Authors: Gao H-J , Chen CL , Fan X , Kim M , Chen SY , Chu CW , Pennycook SJ
Published: July 2020

Thin films of doped perovskite manganites of the type R1-X AxMnO3-y are currently become the focus of intense theoretical and experimental research due to their promising technological implications. However, the microstructure of the film and the interface structure at the atomic level remains unclear. In this report, we will present the atomic structure of the film/substrate interface and the microstructure of the film using a combination of transmission electron microscopy (TEM), Z-contrast scanning transmission microscopy (STEM), and electron energy loss spectroscopy (EELS).

The La0.67Ca0.33MnO3 (LCMO) samples were grown on (001) LaA1O3 (LAO) using pulsed laser deposition. X-ray diffraction indicated the films to be oriented with the [001] directions parallel to the <001> directions of the pseudo-cubic perovskite LAO. Rocking curve measurements using the (002) reflection from the film indicated a full width half maximum of less than 0.3°. A Philips EM-400 electron microscope at 100 kV and a VG HB603 STEM at 300 kV were employed for sample analysis.
Application of Electron Microprobe Age Mapping and Dating of Monazite
Authors: Williams M L , Jercinovic M J
Published: July 2020

High resolution X-ray mapping and dating of monazite (Th, REE-phosphate) using the electron microprobe is an exceptionally powerful technique for structural, metamorphic, and tectonic analysis in geology. Age determination of geologic materials has been conventionally accomplished by mass spectrometry-based analysis of radioisotopic ratios in minerals from hand-picked mineral separates, careful sampling of individual grains out of petrographic thin sections, or by detailed ion probe analysis. Recently, use of the electron microprobe for dating purposes has been attempted. In principal, the concentrations of Th, U and Pb uniquely define the age if non-radiogenic Pb is either not initially present or can be subtracted from the total Pb. Monazite contains high concentrations of Th and U and does not appear to incorporate significant non-radiogenic Pb during mineral growth. Furthermore, monazite is a ubiquitous accessory phase in many metamorphic and igneous rocks, making it ideal for microprobe dating.
An Evaluation of Dating of Diagenetic Xenotime by Electron Microprobe.
Authors: Griffin Brendan J , Forbes Duncan , McNaughton Neal J
Published: July 2020

Xenotime is an igneous mineral commonly present in pegmatite and fractionated granite. Recent studies reveal that it also forms as a diagenetic mineral. Minute (0.1-5 μm) xenotime overgrowths typically crystallise on the surfaces of detrital zircon shortly after sedimentation, in a wide range of siliciclastic sedimentary units. For example, in backscattered electron (BSE) imaging using a scanning electron microscope (SEM), two minute, euhedral, pyramidal, xenotime overgrowths on an oscillatory-zoned detrital Ambergate zircon are evident (figure 1).

Electron microprobe analysis (EMPA) geochronology is a chemical dating method that uses precisely measured concentrations of U, Th, and Pb, and the decay rates of U238, U235, and Th232, to calculate an age for a mineral. The EMPA dating method used in this study to date igneous xenotime and igneous-metamorphic monazite is the chemical isochron method (CHIME). EMPA geochronology is not a widely used technique because of the higher precision of isotopic geochronology.
Drift-Corrected High Magnification Elemental X-Ray Mappng
Authors: Bailey GW , McKernan S , Price RL , Walck SD , Charest P-M , Gauvin R , Kawasaki M , Hosokawa F , Fritz G , Kale N
Published: July 2020

Chemical analysis in a TEM has usually been done as a manual point analysis by forming a probe of an appropriate size for the area of interest. This type of local analysis may provide enough information from the selected area, but these days when materials properties are found to be deeply dependent on chemical distribution, one needs to do a higher dimensional analysis using a systematic line scan or mapping.

Since the advent of the Field Emission Gun (FEG), chemical mapping using X-rays (EDS mapping) or inelastic scattered electrons (Energy Filtering mapping) has become more and more commonly used due to the extremely high resolution information available in the chemical map. Compared to the energy filtered mapping, EDS maps take longer to acquire due to the use of the scanned probe over the area but EDS mapping allows a wider choice of elements to map due to the wider energy range it covers.
Microstructures in Milli-Wave Sintered Silicon Nitride
Authors: Bailey GW , McKernan S , Price RL , Walck SD , Charest P-M , Gauvin R , Brito M E , Valecillos MC , Hirao K , Toriyama M
Published: July 2020

Expectations arised that unique microstructures could be attained by micro- or milli-wave processing of ceramics. To determine possible effects of milli-wave radiation on the microstructure evolution of silicon nitride, a detailed study has been carried out for silicon nitride sintered under conventional resistance heating and under milli-wave radiation (28 GHz). Densification of silicon nitride is achieved by liquid-phase sintering process. The additives such as yttria (Y2O3) and alumina (A12O3) are utilized to form a liquid phase during sintering. Considering the low microwave absorption factor of silicon nitride, heating in a microwave field is associated with the preferential microwave absorption of the additives. Differences in the nature and/or in the absorption factor of the additive will influence the sintering process and hence the final microstructure.
Backscattered Electron Imaging and Microanalysis of Iron-Titanium Oxide Minerals in Fine-Grained Igneous Rocks
Authors: Lowther J S , Brunstad K A
Published: July 2020

Oxides of iron, titanium, and iron & titanium occur as accessory mineral components of most igneous rocks and generally comprise 1-2% of the total rock volume. In the fine-grained rocks the crystals are usually equidimensional and less than 1 mm across. Because most of them are opaque they cannot be examined using polarized transmitted light in the standard petrographic microscope and must be identified by reflected light (1). We have chosen to study these minerals in the SEM using BSE imaging and EDS microanalysis of carbon-coated polished sections of the rocks which contain them. Alhough this does not permit precise identification of the minerals the technique does reveal textural details which cannot be seen with light microscopy and also allows chemical analysis of the grains or parts of the grains. Furthermore, all these the oxide minerals are very easy to see in the BSE images because they are a higher atomic number (Z) than the silicates that form the bulk of the rock.
Fluctuation Microscopy Studies of Amorphous Diamond-Like Carbon Films
Authors: Chen X , Gibson J M , Sullivan J
Published: July 2020

Hydrogen-free amorphous diamond-like carbon films have stimulated great interest because of their useful properties, such as high hardness, chemical inertness, thermal stability, wide optical gap, and negative electron affinity[l]. Consequently, they may have various potential applications in mechanical and optical coatings, MEMS systems, chemical sensors and electronic devices. Amorphous diamond-like carbon films often contains significant amounts of four-fold or sp3 bonded carbon, in contrast to amorphous carbon films prepared by evaporation or sputtering which consist mostly of three-fold or sp2 bonded carbon. The ratio and the structure configurations of these three-fold and four-fold carbon atoms certainly decide the properties of these amorphous diamond-carbon films. Although the ratio of three-fold and four-fold carbon has been studied with Raman spectroscopy and electron-loss-energy spectroscopy, very little has been understood regarding key questions such as how the three-fold and the four-fold carbon atoms are integrated in the film, and what structures those three-fold carbon atoms take.
Real Time Observations of Dislocation-Mediated Plasticity in the Epitaxial Aluminum (110) / Silicon (001) Thin Film System
Authors: Stach EA , Dahmen U , Nix WD
Published: July 2020

The mechanical behavior of metallic thin films on silicon plays a crucial role in the performance and reliability of microelectronic devices. A substantial body of research has focused on experimental methods for determining the mechanical properties of these systems as well as their response to thermomechanical stimuli. Of particular interest is a fundamental understanding of the how these films respond to the thermal expansion stresses that develop during typical microelectronic device fabrication steps.

In this work, we present a series of real time in-situ transmission electron microscopy observations of the thermomechanical response of a model metal film on silicon system. Physical vapor deposition of approximately 50 nm of aluminum onto a clean Si substrate held at 280 °C results in the creation of an epitaxial bicrystalline film with two variants of Al (110) oriented grains. In order to observe a large, uniform area during in-situ TEM thermal cycling, the Si substrate used was a SIMOX structure composed of 300 nm of Si (001) over 370 nm of buried SiO2).
The Crystallography of Co-Alloy Magnetic Media Grown on NiAl Underlayers: Two-&-a-Quarter-D Isotropy Due to Multiplicity of Hexagonal & Cubic Structures
Authors: MoberlyChan Warren J , Dorsey Paul
Published: July 2020

Hard drives in portable computers require media deposited on glass substrates and employ NiAl as the first seed layer to optimize magnetic performance. From observations of a 112 XRD peak [1], a <112> texture has been reported to develop as sputtered films of NiAl thicken; however, synchrotron analysis observes additional cubic peaks [2]. The electron diffraction in this study detects no dominant <112> orientation in NiAl, but rather that the NiAl films (and subsequent cubic underlayers) are closer to 3-D isotropic. Furthermore, the +/-20° range of ﹛1100﹜ orientations observed [3] in the Co media grains grown on NiAl/Cr occurs not because of one (or two) special zone axis relationship(s), nor due to substrate surface finish, but rather as a consequence of multiplicity relationships between the cubic and hexagonal crystals. Although an “increase” in variants is often accepted for an upper film (e.g. bicrystals of [1120] Co on [200] Cr),
TEM Investigations of Aluminum Assisted Crystallization of Amorphous Silicon (α-Si:H)
Authors: Kishore Ram , Hotz Chris , Brown WD , Naseem HA
Published: July 2020

The Crystallization of amorphous silicon (α-Si:H) at lower temperatures is a challenging area of research these days because it will open up the possibilities of fabricating semiconductor devices like thin film transistors (TFT's), solar cells, active matrix liquid crystal display (AMLCD) devices at considearbly lower cost. Various metals e.g. Ni, Cu, Au, Ag and Al have been used to bring down the crystallization temperature of α-Si. We have found that aluminum assisted crystallization can bring down the temperatures of crystallization to as low as 200 °C. The crystallization behavior of α- Si:H has been studied by scanning electron microscopy, Raman spectroscopy, XPS spectroscopy and X-Ray diffraction but very little work has been carried out on microstructural investigation of the material using transmission electron microscopy. We have prepared specimen for die TEM study of α-Si:H and that of crystallized Si obtained by aluminum assisted crystallization. A detailed investigation of the crystallization behavior of α-Si:H using TEM have been carried out.
Scanning Electron Microscopy Studies of Vacuum Evaporated CdCl2 Doped Cadmium Sulphide Films
Authors: Kishore Ram , Korapati Venkatram , Brown WD , Naseem HA
Published: July 2020

CdTe/CdS thin film solar cells are being investigated extensively these days by many workers as an option for low cost photovoltaic applications. In order to achieve high efficiency solar cell it is important that the CdS film should have minimum possible structural defects and reasonably large grain size. The CdS films for CdTe/ CdS solar cell structure are mostly grown on glass substrates by chemical bath deposition (CBD). Although adherent, transparent and conformal films with index of refraction close to single crystal CdS can be grown by CBD, impurity inclusions and micropinholes are a problem there in. Very little work has been carried out to grow CdS films by thermal evaporation in vacuum. In the present work we have grown pure and CdCl2 doped CdS films on glass substrates by thermal evaporation and carried out microstructural investigations of these films using scanning electron microscopy.

Corning 7059 glass of 25.4 x 25.4 x 1.2 mm size were used as substrates for the deposition of CdS as well as CdCl2 doped CdS films.
Clincial Application of Microwave Processing: Biopsy to Block in 3 Hours
Authors: Hastings Cindy L , Crocker Monica J , Walker Patrick D
Published: July 2020

Microwave processing has progressed into a promising procedure for use in the clinical electron microscopy laboratory. In striving for faster turn-around-time in the clinical patient environment, the laboratory microwave has become a very exciting tool. The development of microwave technology enhances the pathologists’ ability to diagnose quickly without compromising quality.

This laboratory's patient sample base is primarily renal biopsies. Tumors and other tissue abnormalities are also diagnosed. Animal and human renal tissue were used for experimentation with the microwave processing protocol. With the need for consistency between the existing resin of choice and standard processing protocol, procedures were developed with these criteria in mind. The standard electron microscopy processing protocol for this laboratory is fixation in either 10% neutral buffered formalin (NBF) or 4% buffered gluteraldehyde followed by post-fixation with 1% osmium tetroxide for 1 hour. The dehydration is performed with gradients of 50% to 100% ethanol followed by a transition solvent of propylene oxide into resin infiltration and polymerization.
Immunolocalization of Rubisco Activase and Rubisco in C3 and C4 Plant Tissues
Authors: Madhavan S , Miller-Goodman M S , Lee K W
Published: July 2020

Ribulose bisphosphate carboxylase/oxygenase (Rubisco), an abundant enzyme in chloroplasts, must be activated by CO2 in order for it to catalyze the carboxylation of ribulose bisphosphate. Rubisco activase, a nuclear encoded chloroplast protein was first identified as a biochemical lesion in the rca mutant of Arabidopsis (1) which lacked this enzyme. Study of Rubisco in this mutant (2) and transgenic tobacco plants with reduced Rubisco activase levels showed that Rubisco could not achieve and maintain an adequate level of activity, in vivo, without an activase. Rubisco activase promotes ‘activation’ of Rubisco by overcoming the deleterious effects of tight binding sugar phosphates and low chloroplast CO2 levels on catalysis and carbamylation (1).

Rubisco activase has been detected in higher plants (3), in unicellular green algae (4,5) and in cyanobacteria (6). Though the presence of Rubisco in guard cell chlroplasts was a subject of controversy, several immunolight and immunoelectron microscopic studies have demonstrated the presence of Rubisco in guard cells (7).
TEM Comparison of Cytologic Specimens Collected in Cytorich Red Preservative and Routine Methods
Authors: McDonald F , Buschmann BO , Boudreaux CW , King JAC
Published: July 2020

Liquid-based technology is becoming more widely used in cytology laboratories for gynecologic and non-gynecologic specimens. Like many other institutions we recently incorporated the liquid-based technology into our laboratory. We have an electron microscope facility in our department and utilize the TEM for ukrastructural evaluation of cytology specimens when additional information is needed. This study compares the preservation of cells from cytology specimens when prepared by routine methods and when placed in the preservative fluid for liquid-based preparations.

Routine smears were made from fine needle aspirations at the time of the procedure or from urine or body fluids on receipt. Some material from three of the non-gynecologic specimens was placed in CytoRich Red (TriPath Imaging, Burlington, NC) fluid. The specimens in CytoRich Red were then centrifuged, and the pellets were placed in 3% glutaraldehyde in cacodylate buffer. Eight body fluid or fine needle aspiration specimens in Plasma-Lyte (Baxter Healthcare Corp., Deerfield, IL) balanced electrolyte solution were centrifuged, and the pellets were placed in 3% glutaraldehyde in cacodylate buffer.
SEM Analysis of Urine Crystals Prepared with Cytorich Red
Authors: Brumit MC , Buschmann B O , Boudreaux C W , McDonald F , King J A C
Published: July 2020

Microscopic evaluation of urine sediment by the cytology laboratory can provide valuable information to the clinician. While some crystal types are considered normal, others are abnormal and indicate disease. Traditional analysis within the cytology laboratory includes direct cytospin preparations and smears of the urine sample. Light microscopy with polarized light is then utilized to examine the slide preparations.

Many cytology laboratories have recently incorporated liquid-based technology for gynecologic and non-gynecologic specimen preparation. Specimens placed in the proprietary fluid are processed according to the manufacturer's directions with the ultimate result of a thin, circular layer of cells on the slide. The advantages of liquidbased methods include concentration of the cells into a thin layer, localization to a small area of the slide, minimization of background debris, and ability to make additional specimens from the same sample. When the liquid-based slide preparations of urine made in our lab were compared to the conventional cytospin smears,
High Throughput in Advanced Sample Preparation
Authors: Shechter Guy , Riga Giorgio
Published: July 2020

As the semiconductor industry paces toward 0.15-micron feature size and below, the visibility of structures becomes a challenge. As a result, the use of higher precision metrology equipment such as FESEM, STEM, TEM and SCM becomes a necessity. TEM analysis today is a less common methodology of analysis. This is due to the time and effort required for the analysis as well as the difficulty of the sample preparation. This publication will share the experience gained in sample preparation for challenging applications such as STEM, TEM and SCM. The main driver will be the focus on short turnover time and high success rates.

In order to perform high-resolution analysis, samples should be transparent to electrons. Optimal thickness would be in the range of 20 to 120 nm (1). Pre-preparation of sample for advanced imaging will determine the final step method required. We used the automated polishing technique for sample preparation and reached 1 to 2 micron thickness.
Broad Ion Beam “Slope Cutting” Technique for Cross Sectional SEM Specimen Preparation of Semiconductors
Authors: Alani R , Hauffe W , Mitro R J
Published: July 2020

Cross sectional SEM specimens are routinely prepared for process monitoring/development, fabrication problem solving and failure analysis in semiconductor industries. A considerable variety of established methods are already in place for production of these specimens. They include: mechanical polishing, manual/automated cleaving, wet chemical etching and focused ion beam (FIB) milling. This report covers a new approach to the preparation of such specimens utilizing a broad ion beam technique. The technique consists of three steps, I) perpendicular “slope cutting” to expose the profile of the layers/features in the starting wafer, II) etching of the cut surface to delineate the microstructures and III) coating the specimen with a conductive thin film to prevent charging effects in the SEM. All three steps are carried out in a dedicated broad ion beam instrument, designed initially to etch and coat SEM specimens in one vacuum chamber [1]. The entire three-step process can be completed in one hour.
A Technique to Prepare Cross Sections of Semiconductor Devices in Small Samples for Transmission Electron Microscopy
Authors: Hudson M V
Published: July 2020

This technique is used to prepare cross sections of semiconductor devices in small samples for analysis by Transmission Electron Microscopy (TEM). These small samples, measuring 100 X 100 X 50 microns, are too small for the manual handling involved in routine mechanical cross sectioning methods. A larger sample, for easier manual handling, is made by gluing the original small sample between a larger piece of silicon and a larger piece of dimpled quartz. The dimpled depression in the quartz is just large enough to surround the original sample. The sample is then mechanically thinned down using a Tripod polisher and the wedge technique. The quartz piece, glued to the top of the original sample, allows the progress of the polish to be monitored as the first side of the cross section is being mechanically polished. The silicon piece, glued to the bottom of the original sample, is used to gauge the final thickness of the wedge produced when polishing the second side of the cross section using the wedge technique.
FIB Dimpling: A Method for Preparing Plan-View TEM Specimens
Authors: Klepeis Stanley , Domenicucci Anthoney , Hunt Donald , Anderson Ron
Published: July 2020

Failure analysis in the microelectronic industry via TEM has long dealt with the specimen preparation spatial resolution problem—the ability to prepare useful TEM specimens at very small pre-selected locations. This problem is made more difficult with time because, while device structures become smaller and more dense, the failure rate of individual devices is extremely low and dropping. TEM analysts, therefore, must prepare specimens that optimally present a single faulty component within an ocean of a billion or more similar components. Sophisticated electrical testers can find the faulty component and transfer its coordinates to a FIB tool where the failure can be marked. Cross section TEM specimens are appropriate when it is suspected that the failure is caused by a defect in the stack of metal and insulators constructed on the top of the device substrate (usually silicon). Plan view TEM specimens are appropriate when the electrical signature of the failure indicates that the fault lies in the Si itself-dislocations or some other crystal defect.
Automation of Focused Ion Beam (FIB) Sample Preparation
Authors: Young R J
Published: July 2020

The use of focused ion beam (FIB) systems is well established as a sample preparation and imaging tool in a wide range of applications, most notably, in the semiconductor and data storage industries, but also within material and biological sciences (Figs. 1-3). The real benefit of the FIB is that the same ion beam that is used for material removal and deposition is also used for imaging the sample, which results in highly precise and localized sample preparation. In addition, the FIB can be used to prepare samples through multiple layers with different material properties, and allows the rest of specimen to be kept intact for further analysis or processing. FIB is most commonly used to prepare samples for the transmission electron microscope (TEM), the scanning electron microscope (SEM), and for the FIB itself. The FIB, which is an imaging tool in its own right, can produce secondary-electron and -ion images and collect secondary ion mass spectrometry (SIMS) data.
Redeposition Effects in TEM Sample Preparation of Feal-Based Metal Matrix Composites using the Focused Ion Beam Miller
Authors: Cairney Julie M , Munroe Paul R
Published: July 2020

The focused ion beam miller (FIB) has been widely used in the semiconductor industry for many years, but only recently has its potential as a tool for materials science been recognised. The FIB uses a highly energetic beam of gallium ions to sputter material such that it can precisely section, as well as image, areas of interest. The FIB can be used to create crosssections, which can be examined in the FIB or in a scanning electron microscope (SEM). Cross sections can be made from delicate samples or samples in which a specific area needs to be viewed, for example to check the thickness of coatings or for failure analysis.

The FIB may also be used to prepare transmission electron microscope (TEM) specimens [1]. Extremely site-specific thin areas may be prepared with high positional accuracy from heterogeneous samples such as composites or layered structures.
Site Specific TEM Analysis of Micrometer-Sized Particles with the FIB Lift-Out Technique
Authors: Lomness J K , Giannuzzi L A , Hampto M D
Published: July 2020

The focused ion beam (FIB) instrument offers an efficient and reproducible approach for obtaining electron transparent membranes of uniform thickness for TEM analysis. Thus, the use of the FIB to investigate numerous types of materials has grown tremendously recently. Prenitzer et al. demonstrated the ability to acquire TEM specimens from individual Zn powder particles using the FIB lift-out (LO) specimen preparation technique. The 10 μm × 100 μm Zn powders particles were larger than the 5 μrn x 20 μm FIB LO specimen and therefore the LO technique could be directly applied to an individual powder particle. This paper will discuss a novel approach for the preparation of site specific micrometer-sized particles for TEM analysis using the FIB LO technique. The uniqueness of the technique described herein is that site specific TEM LO specimens may be obtained from regions which are smaller than the conventional dimensions of the LO specimen.
FIB Techniques for Analysis of Metallurgical Specimens
Authors: Phaneuf Michael W , Li Jian
Published: July 2020

Focused ion beam (FIB) microscopes, the use of which is well established in the semiconductor industry, are rapidly gaining attention in the field of materials science, both as a tool for producing site specific, parallel sided TEM specimens and as a stand alone specimen preparation and imaging tool.

Both FIB secondary ion images (FIB SII) and FIB secondary electron images (FIB SEI) contain novel crystallographic and chemical information. The ability to see “orientation contrast” in FIB SEI and to a lesser extent SII is well known for cubic materials and more recently stress-free FIB sectioning combined with FIB imaging have been shown to reveal evidence of plastic deformation in metallic specimens. Particularly in hexagonal metals, FIB orientation contrast is sometimes reduced or eliminated by the FIB sectioning process. We have successfully employed FIB gas assisted etching during FIB sectioning using XeF2 for zirconium alloys and Cl2 for zinc coatings on steels to retain orientation contrast during subsequent imaging.
Assessment of Deformation using the Focused Ion Beam Technique
Authors: Burke MG , Duda PT , Botton G , Phaneuf M W
Published: July 2020

Focused Ion Beam (FIB) micromachining techniques have gained significant attention over the past few years as a promising method for the preparation of a variety of metallic and nonmetallic materials for subsequent characterization using transmission electron microscopy (TEM) The advantage of the FIB in terms of site specificity and speed for the preparation of uniform electron transparent sections has opened a wide range of potential applications in materials characterization. The ability to image the sample in the FIB can also provide important microstructural data for materials analysis. In this study, both conventionally electropolished and FIB-ed specimens were prepared in order to characterize the microstructure of a commercially-produced tube of Alloy 600 (approximately Ni-15 Cr-10 Fe- 0.05 C). The electropolished samples were prepared using a solution of 20% HClO4 - 80% CH3OH at ∼-40°C. The FIB sections were obtained from a cross-section of the tube that had been mechanically thinned to ∼100 μm. The section was thinned in a Micrion 2500 FIB system with a Ga ion beam at 50 kV accelerating voltage.
A Stress Relief Method to Control Warping of Focused Ion Beam Prepared Membranes for Transmission Electron Microscopy
Authors: Rossie BB , Stevie FA , Shofner TL , Brown SR , Irwin RB
Published: July 2020

The continued decrease in microelectronic feature dimensions has led to a reliance on the focused ion beam (FIB) for site-specific transmission electron microscopy (TEM) specimen preparation. To maximize the capabilities of the FIB, methods must be developed to consistently produce specimens thin enough to generate TEM lattice images. The limiting factor in producing quality TEM specimens by either the traditional or lift-out method is the final thickness of the specimen.

The FIB is used to prepare TEM specimens by removing the bulk material that surrounds a desired feature by sputtering with a focused gallium ion beam. Successively lower beam currents are used to sputter away material until an electron transparent membrane (-0.2 μm) containing the desired feature remains. For a 300 keV TEM, lattice imaging of silicon requires additional membrane thinning to less than 0.05 μm.

The loss of rigidity during the thinning process makes the membrane highly prone to deformation due to residual stresses, linear expansion, and ion beam interaction.
Calibration Method for Elemental Quantification
Authors: Vartuli C B , Stevie F A , Giannuzzi L A , Shofner T L , Purcell B M , Irwin R B , McKinley JM , Wesson R J
Published: July 2020

Energy Dispersive Spectrometry (EDS) is generally calibrated for quantification using elemental standards. This can introduce errors when quantifying non-elemental samples and does not provide an accurate detection limit. In addition, variations between analysis tools can lead to values that differ considerably, especially for trace elements. By creating a standard with an exact trace composition, many of the errors inherent in EDS quantification measurements can be eliminated.

The standards are created by high dose ion implantation. For ions implanted into silicon, a dose of 1E16 cm-2 results in a peak concentration of approximately 1E21 cm-3 or 2% atomic. The exact concentration can be determined using other methods, such as Rutherford Backscattering Spectrometry (RBS) or Secondary Ion Mass Spectrometry (SIMS). For this study, SIMS analyses were made using a CAMECA IMS-6f magnetic sector. Measurement protocols were used that were developed for high concentration measurements, such as B and P in borophosphosilicate glass (BPSG).
Matrix Protein Structural Analysis of Brain Aneurysms by Polarizing Microscopy
Authors: Canham Peter B , Finlay Helen M , Humphrey Jay D
Published: July 2020

The wall of saccular brain aneurysms, lesions that develop at the fork regions of human brain arteries, is a layered multidirectional fabric of fibrous collagen. The wall tissue has the mechanical features of high elastic stiffness and a low tensile strength compared to adjacent arteries. Arterial blood pressure within the sac of an aneurysm stresses the wall in all tangential directions; thus an area of mechanical weakness may be characterized by an area lacking fibre strength, or an area with inadequately aligned fibres.

The collagen fibres of the wall are birefringent, with many fibre types, similar to wound healing skin (types I, III, IV, V, VI) The known correlation between fibre birefringence and tissue strength for dermal wound healing3 provided the opportunity in this research to calculate strength maps to compare one lesion from another, and to make regional comparisons around a single lesion.
Blowing Up the Stiff Balloon: X-Ray Microtomography Reveals Decrease in Arterial Distensibility in Pulmonary Hypertension
Authors: Johnson Roger H , Karau Kelly L , Molthen Robert C , Haworth Steven T , Dawson Christopher A
Published: July 2020

We are developing nondestructive and non-traumatic imaging methods to quantitatively assess structural and mechanical properties of vascular trees and other complex biological systems. We are applying these methods to studies of vascular remodeling in rodent models of disease. Quantitative vascular tree morphometry has, in the past, been carried out using corrosion casting methods which supply valuable information, but are destructive and tend to be tedious, in particular with regard to associating vessel segment measurements accurately with their positions in the intact tree hierarchy. One of our goals is to refine imaging methods capable of quantifying mechanical, as well as anatomical properties, by virtue of their ability to rapidly acquire multiple image volumes of the same structure under various conditions, all in a nearphysiological state.

Using the micro-CT scanner shown in Figure 1, consisting of a microfocal x-ray tube, specimen stage and image intensifier coupled to a 10242, 12-bit CCD camera, we acquire magnified (3-9X), transmitted x-ray projections of contrast enhanced, excised rat lungs or lung lobes.
Structural Studies of Fibrinolysis: How to Disassemble a Clot
Authors: Weisel John W , Veklich Yuri , Collet Jean-Philippe
Published: July 2020

Fibrin clot formation is necessary for maintaining the integrity of the vasculature via the physiological processes of hemostasis and wound healing and is also involved in pathological processes, such as thrombosis and atherosclerosis. Fibrinolysis, or the dissolution of the clot, is necessary to remove clots so that they do not become obstructive. There must be a dynamic balance between clot formation and fibrinolysis to prevent either bleeding or thrombosis. Although the biochemical process of fibrinolysis is well known, less has been known about the physical process of lysis. In these studies, the surface of digested clots were examined by scanning electron microscopy, the products released were visualized by transmission electron microscopy and the process of lysis was followed in real time by confocal microscopy.

Fibrin is degraded by the fibrinolytic system, in which a plasminogen activator converts plasminogen to plasmin, a serine protease that cleaves specific bonds in fibrin leading to solubilization.
Microvenous Valvular Mapping in the Human Lower Extremity. Valvular Density Alone Cannot Account for Sites of Chronic Venous Stasis and Ulceration.
Authors: Aharinejad S , Nedwed S , Michlits W , Dunn RM , Nourani F , Abraham D , Vernadakis A , Marks SC
Published: July 2020

In the leg venous valves isolate the blood into short columns and thus relieve the vessel wall from the gravitational force of blood columns that would otherwise be several feet in length. Class 6 chronic venous insufficiency is associated with abnormal venous hemodynamics and associated tissue-related abnormalities termed lipodermatosclerosis, accompanied by ulceration. Ingenious surgical techniques have focused on correction of the abnormal hemodynamics by repair, reconstruction, or transplantation of venous valves to the deep venous system of the lower extremity with varying success rates. We have applied free scapular fasciocutaneous flaps to successfully reconstruct recalcitrant grade 6 venous insufficiency ulcers in the lower extremity. We have noticed such ulcers frequently in medial malleolar, lateral malleolar or dorsum pedis but never in the region of the gastrocnemius or peroneus muscles. This fact prompted us to examine the microvenous valvular anatomy in segments of human leg.
Microarchitecture of the Terminal Afferent Vessels in the Rat Liver. A SEM Study of Vascular Corrosion Casts.
Authors: Spornitz Udo M , Bartuskova Irena , Morson Gianni
Published: July 2020

The blood supply of the liver is of dual origin, namely the hepatic artery and the portal vein. The physiological implications of this dual blood supply are well understood (1), the morphological details of the terminal afferent vessels, however, still need to be further investigated. Particularly the various possible types of entry of the terminal afferent vessels into the sinusoids are not yet fully understood. With the aid of a newly developed method, i.e. the combination of detection of a marker substance (with the aid of EDX) and scanning electron microscopy, many of the morphological parameters have been elucidated (2). This new method involves the injection of the liver from two sides (arterial and portal vessels) with methacrylate or Mercox containing either of two different marker substances, both of which can be detected with the aid of an EDX detector. Thus the terminal afferent vessels can easily be told apart (2, 3).
Ultrastructure of a Benign Thymoma
Authors: Siew S
Published: July 2020

A thymoma is a tumor which arises from the epithelial cells of the thymus. Despite the progressive involution of the thymus post-puberty, the peak incidence of thymomas is in adults, after the age of 40. Owing to the normal anatomic location of the thymus in the antero-superior mediastinum, thymomas account for 20-30% of masses in that situation, and, they have to be differentiated from other neoplasms which may be found in the anterior mediastinam, such as, lymphocytic lymphoma, Hodgkin's disease, Germinoma (seminoma), Thymic carcinoid tumor, oat cell carcinoma and parathyroid adenoma.

Embryologically, the thymus develops as an outgrowth of epithelial cells from the third pharyngeal pouches in association with the inferior parathyroid glands and migrates from the neck to the mediastinum. In embryonic life, blood borne stem cells from the yolk sac are seeded into the thymus which becomes the primary lymphoid organ. Within the thymus, the primitive stem cells differentiate into lymphocytes, which proliferate and differentiate into T-lymphocytes (thymus-dependent, thymocytes). Some of the T-lymphocytes are released into the blood stream and populate peripheral lymphoid organs. They constitute 60-70% of circulating lymphocytes.