Structural and Chemical Microanalysis of Oxygen-Bearing Precipitates in Silicon

1982 ◽  
Vol 14 ◽  
Author(s):  
R.W. Carpenter ◽  
I. Chan ◽  
H.L. Tsai ◽  
C. Varker ◽  
L.J. Demer
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Low Density ◽  
X Ray ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra ◽  
Metallic Impurities ◽  
Stage Heat Treatment ◽  
Plate Type

ABSTRACTPrecipitation in CZ-silicon during post-growth two-stage heat treatment has been examined using the methods of high resolution analytical electron microscopy. Electron transparent specimens prepared from these specimens, exhibited a low density of plate type precipitates on {100} planes. Microdiffraction experiments showed the precipitates to be consistently non-crystalline. Electron energy loss spectra showed that the precipitates contained oxygen, but carbon was not detected. It was found that carbon artifact absorption edges could be induced in spectra by specimen contamination in the microscope. The use of a low temperature stage eliminated this problem. Complementary characteristic x-ray microanalysis showed that metallic impurities had not segregated to these precipitates in this particular case, although this has been observed elsewhere.

NiO Test Specimens for Analytical Electron Microscopy: Round-Robin Results

1995 ◽  
Vol 1 (4) ◽  
pp. 143-149 ◽  
Author(s):  
J.C. Bennett ◽  
R.F. Egerton
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Test Specimen ◽  
Analytical Electron Microscopy ◽  
X Rays ◽  
Elemental Ratios ◽  
X Ray ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Nio Films

Improvements in instrumentation for energy-dispersive X-ray microanalysis (EDX) and electron energy-loss spectroscopy (EELS) have underlined the need for suitable standards for measuring performance. We report the results from several laboratories that were supplied with a test specimen consisting of a thin film of nickel oxide supported on a molybdenum grid. The Ni-Kα/Mo-Kα count ratio was used as an indication of number of stray electrons and/or X-rays in the TEM column; the Ni-Kα peak/background ratio provided a measure of the total background in the EDX spectrum, including bremsstrahlung contributions and the effect of detector electronics. By providing values typical of current instrumentation, the results illustrate how the test specimen can be used to evaluate TEM/EDX systems prior to purchase, during installation, and (periodically) during operation. The NiO films were also used to test EELS acquisition and quantification procedures: measured Ni/O elemental ratios were all within 10% of stoichiometry.

Analytical Electron Microscopy of a Polymer Blend

1985 ◽  
Vol 43 ◽  
pp. 80-81
Author(s):  
T. Haddock ◽  
S.J. Krause ◽  
S. Kumar ◽  
W.W. Adams
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Polymer Blend ◽  
Analytical Electron Microscopy ◽  
High Strength ◽  
X Ray ◽  
Analytical Electron ◽  
Flexible Coil ◽  
Electron Energy Loss ◽  
Beam Damage

A polymer blend which is composed of poly-p-phenylene benzobisthiazole (PBT) and poly-2,5(6)benzimidazole (ABPBI) has been processed into both a phase-separated material and a “molecular composite”. In the molecular composite, the PBT and ABPBI components are dispersed at a scale finer than 3 nm. This results in high mechanical properties as the rod-like, high strength PBT reinforces the flexible-coil ABPBI matrix. In the phase- separated blend, micron-sized aggregates form within a more ductile matrix. This study qualitatively examines the structure and composition of the phase- separated 20% PBT / 80% ABPBI blend using the analytical electron microscopy (AEM) techniques of energy dispersive x-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), and microdiffraction. Beam damage of the components is also considered.

Detection limits for Analytical Electron Microscopy with Electron Energy Loss Spectrometry and energy-dispersive x-ray spectrometry

1993 ◽  
Vol 51 ◽  
pp. 594-595
Author(s):  
Dale E. Newbury ◽  
Richard D. Leapman
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Cross Section ◽  
Analytical Electron Microscopy ◽  
Energy Dispersive ◽  
X Ray ◽  
Electron Energy Loss Spectrometry ◽  
Analytical Electron ◽  
Electron Energy Loss

The measurement of trace level constituents, arbitrarily defined for this study as concentration levels below 1 atom percent, has always been considered problematic for analytical electron microscopy (AEM) with energy dispersive x-ray spectrometry (EDS) and electron energy loss spectrometry (EELS). In a landmark study of various microanalysis techniques, Wittry evaluated the influence of various instrumental factors (source brightness, detection efficiency, accumulation time) and physical factors (cross section, peak-to-background) upon detection limits. Although the ionization cross section, fluorescence yield, and collection efficiency favor EELS over EDS, the peak-to-background ratio of EELS spectra is much lower than that of EDS spectra, leading Wittry to suggest that the limit of detection should be 0.1 percent for EDS and 1 percent for EELS for practical measurement conditions. Recent developments in parallel detection EELS (PEELS) indicate that a re-evaluation of the situation for trace constituent determination is needed for those elements characterized by "white line" resonance structures at the ionization edge.

Analytical Electron Microscopy of Precipitates in Ion-Implanted Mgal2O4 Spinel

1994 ◽  
Vol 373 ◽  
Author(s):  
N. D. Evans ◽  
S. J. Zinkle ◽  
J. Bentley
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Volume Fraction ◽  
Analytical Electron Microscopy ◽  
Metallic Aluminum ◽  
X Ray ◽  
Electron Energy Loss Spectrometry ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Ion Implanted

AbstractAnalytical electron microscopy (AEM) has been used to investigate precipitates in MgAl2O4 spinel implantated with Al+, Mg+, or Fe2+ ions. Experiments combining diffraction, energy dispersive X-ray spectrometry (EDS), electron energy-loss spectrometry (EELS), and energy-filtered imaging were employed to identify and characterize precipitates observed in the implanted ion region. Diffraction studies suggested these are metallic aluminum colloids, although EELS and energy-filtered images revealed this to be so only for the Al+ and Mg+ implantations, but not for Fe2+ ion implantations. Multiple-least-squares (MLS) fitting of EELS plasmon spectra was employed to quantify the volume fraction of metallic aluminum in the implanted ion region. Energy-filtered plasmon images of the implanted ion region clearly show the colloid distribution in the Al+ and Mg+ implanted spinel. Energy-filtered images from the Fe2+ ion implanted spinel indicate that the features visible in diffraction contrast cannot be associated with either metallic aluminum or iron-rich precipitates.

Analytical Electron Microscopy (AEM) of Meningeal Cells Exposed to Particulate Cobalt During Studies of Experimental Epilepsy

1982 ◽  
Vol 40 ◽  
pp. 186-187
Author(s):  
R.G. Frederickson ◽  
R.G. Ulrich ◽  
J.L. Culberson
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Experimental Epilepsy ◽  
Metallic Cobalt ◽  
Experimental Animals ◽  
X Ray ◽  
Brain Surface ◽  
Meningeal Cells ◽  
Analytical Electron ◽  
The Brain

Metallic cobalt acts as an epileptogenic agent when placed on the brain surface of some experimental animals. The mechanism by which this substance produces abnormal neuronal discharge is unknown. One potentially useful approach to this problem is to study the cellular and extracellular distribution of elemental cobalt in the meninges and adjacent cerebral cortex. Since it is possible to demonstrate the morphological localization and distribution of heavy metals, such as cobalt, by correlative x-ray analysis and electron microscopy (i.e., by AEM), we are using AEM to locate and identify elemental cobalt in phagocytic meningeal cells of young 80-day postnatal opossums following a subdural injection of cobalt particles.

The effect of small additions of Cu on precipitation in Al-Mg-Si alloys

1990 ◽  
Vol 48 (2) ◽  
pp. 442-443
Author(s):  
M. Tamizifar ◽  
G. Cliff ◽  
R.W. Devenish ◽  
G.W. Lorimer
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Argon Atmosphere ◽  
Age Hardening ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Analytical Electron ◽  
Scanning Transmission

Small additions of copper, <1 wt%, have a pronounced effect on the ageing response of Al-Mg-Si alloys. The object of the present investigation was to study the effect of additions of copper up to 0.5 wt% on the ageing response of a series of Al-Mg-Si alloys and to use high resolution analytical electron microscopy to determine the composition of the age hardening precipitates.The composition of the alloys investigated is given in Table 1. The alloys were heat treated in an argon atmosphere for 30m, water quenched and immediately aged either at 180°C for 15 h or given a duplex treatment of 180°C for 15 h followed by 350°C for 2 h2. The double-ageing treatment was similar to that carried out by Dumolt et al. Analyses of the precipitation were carried out with a HB 501 Scanning Transmission Electron Microscope. X-ray peak integrals were converted into weight fractions using the ratio technique of Cliff and Lorimer.

The Use of ELNES for Microanalysis

1999 ◽  
Vol 5 (S2) ◽  
pp. 664-665
Author(s):  
A.J. Craven ◽  
M. MacKenzie
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Analytical Electron Microscopy ◽  
Local Environment ◽  
Edge Structure ◽  
Similar Shape ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Combining Information

The performance of many materials systems depends on our ability to control the distribution of atoms on a nanometre or sub-nanometre scale within those systems. This is as true for steels as it is for semiconductors. A key requirement for improving their performance is the ability to determine the distribution of the elements resulting from processing the material under a given set of conditions. Analytical electron microscopy (AEM) provides a range of powerful techniques with which to investigate this distribution. By combining information from different techniques, many of the ambiguities of interpretation of the data from an individual technique can be eliminated. The electron energy loss near edge structure (ELNES) present on an ionisation edge in the electron energy loss spectrum reflects the local structural and chemical environments in which the particular atomic species occurs. Thus it is a useful contribution to the information available. Since a similar local environment frequently results in a similar shape, ELNES is useful as a “fingerprint”.

scholarly journals Analytical electron microscopic evaluation of the effects of paraformaldehyde pretreatment on the reaction of glutaraldehyde with biogenic amines.

1982 ◽  
Vol 30 (5) ◽  
pp. 481-486 ◽  
Author(s):  
R E McClung ◽  
J Wood
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
Spectrographic Analysis ◽  
Electron Microscopic ◽  
X Ray ◽  
Microscopic Evaluation ◽  
Analytical Electron ◽  
Dense Product

Analytical electron microscopy was used to determine the quantitative effects of paraformaldehyde pretreatment on the formation of the biogenic amine-glutaraldehyde-chrome complex. Pretreatment with paraformaldehyde prevented the glutaraldehyde-chrome reaction with norepinephrine in the rat adrenal medulla. In contrast to the effect of paraformaldehyde on norepinephrine, pretreatment did not prevent the chrome reaction in serotonin-containing argentaffin cells of the gut. X-Ray energy spectrographic analysis revealed a significant decrease in chrome content in the paraformaldehyde treated tissue, but sufficient chrome did react to produce an electron-dense product. Thus by treating tissue with paraformaldehyde prior to the glutaraldehyde chrome procedure, serotonergic sites may be differentiated from catecholaminergic areas at the electron microscopic level.

Mixed-layer mica-chlorite in very low-grade metaclastites from the Malàguide Complex (Betic Cordilleras, Spain)

Clay Minerals ◽  
2001 ◽  
Vol 36 (3) ◽  
pp. 307-324 ◽  
Author(s):  
M. D. Ruiz Cruz
Keyword(s):  
Electron Microscopy ◽  
Mixed Layer ◽  
Analytical Electron Microscopy ◽  
Low Grade ◽  
X Ray ◽  
Betic Cordilleras ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Microscopy Data ◽  
Ray Patterns

AbstractMixed-layered phyllosilicates with composition intermediate between mica and chlorite were identified in very low-grade metaclastites from the Malàguide Complex (Betic Cordilleras, Spain), and studied by X-ray diffraction, and transmission and analytical electron microscopy. They occur both as small grains in the rock matrix, and associated with muscovitechlorite stacks. Transmission electron microscope observations revealed a transition from chlorite to ordered 1:1 interstratifications through complex 1:2 and 1:3 interstratifications. Analytical electron microscopy data indicate a composition slightly different from the sum of discrete trioctahedral chlorite and dioctahedral mica. The types of layer transitions suggest that mixed-layer formation included two main processes: (1) the replacement of a brucite sheet by a cation sheet in the chlorite structure; and (2) the precipitation of mica-like layers between the chlorite layers. The strongest diffraction lines in oriented X-ray patterns are: 12.60 Å (002), 7.98 Å (003), 4.82 Å (005) and 3.48 Å (007).

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