An Electron Backscattered Diffraction Specimen Preparation Technique for High Resolution Serial Sectioning

2000 ◽  
Vol 6 (S2) ◽  
pp. 950-951
Author(s):  
M.A. Wall ◽  
A.J. Schwartz ◽  
L. Nguyen
Keyword(s):  
High Resolution ◽  
Serial Section ◽  
Orientation Imaging Microscopy ◽  
Side Surface ◽  
Primary Objective ◽  
Measuring System ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Serial Sectioning ◽  
Electron Backscattered Diffraction

A high-resolution serial sectioning specimen preparation technique is described for acquisition of electron backscattered diffraction orientation imaging microscopy (OIM) data. The primary objective is to develop a method to reproducibly remove a controlled thickness of material (a serial section) from a polycrystalline Ta sample while producing quality surfaces for OIM imaging. This is integrated with the ability to accurately measure the amount of material removed with each iteration and experimentally register the ensuing OIM scans.A Si metrology device is fabricated by lithographic techniques to facilitate the measurement of the amount of material removed with each lapping iteration and the alignment of each serial section image. This metrology device contains a herringbone pattern with two orthogonal etched lines oriented at 45 degrees and one vertical line normal to the OIM surface. The metrology device is epoxied to a polished side surface of the Ta sample. Due to the orthogonality of the lines, the thickness of material removed equals one-half the total linear motion of the etched lines as seen in cross-section. To accurately measure the distance between the grooves after each lapping iteration, a high-resolution (0.1 μm) linear measuring system is attached to the table of a light metallograph.

Preparation of BiCaSrCuO specimens for High-Resolution Transmission Electron Microscopy

1989 ◽  
Vol 47 ◽  
pp. 714-715
Author(s):  
K. Fortunati ◽  
M. Fendorf ◽  
M. Powers ◽  
C.P. Burmester ◽  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Carbon Film ◽  
Fine Powder ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Pure Ethanol ◽  
Transmission Electron ◽  
Porous Microstructure

Transmission electron microscopy, in particular high-resolution TEM, is proving to be a valuable tool in the continuing effort to characterize and understand the “high-Tc” superconducting oxides. Since specimen quality is of critical importance in high-resolution studies, care must be taken to choose the most appropriate specimen preparation technique for the material under study. The BiCaSrCuO material investigated here was in the form of small, sintered pellets with a porous microstructure which consists of small, randomly oriented, poorly connected, plate-like grains (see Figure 1). We have found that this morphology can significantly effect the production of suitable TEM specimens.The simplest and most rapid specimen preparation method employed consists of crushing a small amount of the starting material to a fine powder in an agate mortar and suspending the powder in pure ethanol or propanol. An eye dropper or syringe is then used to transfer 4-6 drops of the suspension onto a holey carbon film supported on a mesh grid, thus effectively dispersing the powder across the grid. A strong tendency for the crystal to cleave along (001) planes, due to the weak bonding between BiO layers, results in flake-like particles which exhibit a preferred [001] orientation on the grid. A high-resolution image of a specimen prepared using this method is shown in Figure 2. We have observed that some specimens produced in this manner are unstable under a 200kV beam (with LaB6 filament), with heavy damage occurring within the time that a through-focus series of micrographs can be exposed. It is also important to note that since separation along grain boundaries occurs during crushing, this method is not an appropriate choice for imaging grain boundary structures.

In-Situ Ion Milling in the Transmission Electron Microscope (TEM) Outlook to a New Preparation Technique

2001 ◽  
Vol 7 (S2) ◽  
pp. 932-933
Author(s):  
Peter Gnauck ◽  
Claus Burkhardt ◽  
Erich Plies ◽  
Wilfried Nisch
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Analytical Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Specimen Preparation ◽  
Specimen Thickness ◽  
Preparation Technique ◽  
Ion Milling ◽  
Transmission Electron

Recent developments in transmission electron microscopy put high demands on specimen preparation. in general the imaging quality is not limited by the performance of the microscope but by the quality of the specimen. in order to achieve a spatial resolution of 0.1 nm in HRTEM undamaged samples with a thickness below 10 nm are required. in energy filtering analytical electron microscopy (EFTEM), a constant specimen thickness over large areas and very low contamination is needed.Conventional ion-milling techniques for TEM specimen preparation are essentially blind. Thus, it is left to chance whether the specimen detail of interest is suitable for TEM-imaging (many specimen areas are too thick). Another problem is the reaction of the specimen with the atmosphere during the transfer from the preparation stage to the microscope, which makes it very difficult to obtain the clean specimen surfaces that are needed in analytical EFTEM. Especially in high-resolution electron microscopy and electron holography the formation of amorphous oxidation and contamination layers on otherwise crystalline materials may seriously reduce the quality of high resolution images of the crystal structure.

Contrast from epitaxially sandwiched macromolecules

1978 ◽  
Vol 36 (2) ◽  
pp. 226-227
Author(s):  
M. Talianker ◽  
D.G. Brandon
Keyword(s):  
Gold Film ◽  
Lattice Defect ◽  
Gold Foil ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Resolution Limit ◽  
Transmission Electron ◽  
Crystal Lattice Defect ◽  
Void Effect ◽  
Lattice Resolution

A new specimen preparation technique for visualizing macromolecules by conventional transmission electron microscopy has been developed. In this technique the biopolymer-molecule is embedded in a thin monocrystalline gold foil. Such embedding can be performed in the following way: the biopolymer is deposited on an epitaxially-grown thin single-crystal gold film. The molecule is then occluded by further epitaxial growth. In such an epitaxial sandwich an occluded molecule is expected to behave as a crystal-lattice defect and give rise to contrast in the electron microscope.The resolution of the method should be limited only by the precision with which the epitaxially grown gold reflects the details of the molecular structure and, in favorable cases, can approach the lattice resolution limit.In order to estimate the strength of the contrast due to the void-effect arising from occlusion of the DNA-molecule in a gold crystal some calculations were performed.

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

Ultramicrotomy as a Technique for Materials Specimen Preparation

1990 ◽  
Vol 48 (2) ◽  
pp. 428-429
Author(s):  
S.R. Glanvill
Keyword(s):  
Materials Science ◽  
Structural Information ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Cross Sectional ◽  
Surfaces And Interfaces ◽  
Beam Analysis ◽  
Flat Embedding ◽  
20 Nm ◽  
Sectional Analysis

This paper summarizes the application of ultramicrotomy as a specimen preparation technique for some of the Materials Science applications encountered over the past two years. Specimens 20 nm thick by hundreds of μm lateral dimension are readily prepared for electron beam analysis. Materials examined include metals, plastics, ceramics, superconductors, glassy carbons and semiconductors. We have obtain chemical and structural information from these materials using HRTEM, CBED, EDX and EELS analysis. This technique has enabled cross-sectional analysis of surfaces and interfaces of engineering materials and solid state electronic devices, as well as interdiffusion studies across adjacent layers.Samples are embedded in flat embedding moulds with Epon 812 epoxy resin / Methyl Nadic Anhydride mixture, using DY064 accelerator to promote the reaction. The embedded material is vacuum processed to remove trapped air bubbles, thereby improving the strength and sectioning qualities of the cured block. The resin mixture is cured at 60 °C for a period of 80 hr and left to equilibrate at room temperature.

High-resolution microscopy of twin boundaries in gold

1987 ◽  
Vol 45 ◽  
pp. 260-261
Author(s):  
William Krakow ◽  
David A. Smith
Keyword(s):  
High Resolution ◽  
Specimen Preparation ◽  
Gold Films ◽  
Boundary Area ◽  
Transmission Electron ◽  
Recent Developments ◽  
Tilt Boundaries ◽  
High Resolution Microscopy ◽  
Twist Boundaries

Recent developments in specimen preparation, imaging and image analysis together permit the experimental determination of the atomic structure of certain, simple grain boundaries in metals such as gold. Single crystal, ∼125Å thick, (110) oriented gold films are vapor deposited onto ∼3000Å of epitaxial silver on (110) oriented cut and polished rock salt substrates. Bicrystal gold films are then made by first removing the silver coated substrate and placing in contact two suitably misoriented pieces of the gold film on a gold grid. Controlled heating in a hot stage first produces twist boundaries which then migrate, so reducing the grain boundary area, to give mixed boundaries and finally tilt boundaries perpendicular to the foil. These specimens are well suited to investigation by high resolution transmission electron microscopy.

High-resolution observation of sintered alumina (Al2O3) using the specimen-heated and electron-beam-induced conductivity method in a UHR-SEM

1994 ◽  
Vol 52 ◽  
pp. 1046-1047
Author(s):  
K. Ogura ◽  
T. Suzuki ◽  
C. Nielsen
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Specimen Preparation ◽  
Conductivity Method ◽  
Fine Grain ◽  
Grain Structures ◽  
Resolution Observation ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Charging Effect

In spite of the complicated specimen preparation, Transmission Electron Microscopes (TEM) have traditionally been used for the investigation of the fine grain structures of sintered ceramics. Scanning Electron Microscopes (SEM) have not been used much for the same purpose as TEM because of poor results caused by the specimen charging effect, and also the lack of sufficient resolution. Here, we are presenting a successful result of high resolution imaging of sintered alumina (pure Al2O3) using the Specimen Heated and Electron Beam Induced Conductivity (SHEBIC) method, which we recently reported, in an ultrahigh resolution SEM (UHR-SEM). The JSM-6000F, equipped with a Field Emission Gun (FEG) and an in-lens specimen position, was used for this application.After sintered Al2O3 was sliced into a piece approximately 0.5 mm in thickness, one side was mechanically polished to get a shiny plane for the observation. When the observation was started at 20 kV, an enormous charging effect occured, and it was impossible to obtain a clear Secondary Electron (SE) image (Fig.1).

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