Charge Contrast: Some ESEM Observations of A New/Old Phenomenon

1998 ◽  
Vol 4 (S2) ◽  
pp. 292-293 ◽  
Author(s):  
Eric Doehne
Keyword(s):  
Cross Sections ◽  
Secondary Electron ◽  
Low Voltage ◽  
Environmental Scanning Electron Microscopy ◽  
Personal Communication ◽  
Environmental Scanning ◽  
Contrast Imaging ◽  
The Past ◽  
Contrast Mechanisms ◽  
Scanning Electron

Over the past few years there have been occasional reports of unusual secondary electron contrasts in certain nonmetallic materials using conventional (CSEM-Johansen et al, 1997), low voltage (LV-SEM-Harker et al, 1993; Harker et al, 1994) and environmental scanning electron microscopy (ESEM-Griffin, 1997; T. Hardt, personal communication) which have documented novel contrast mechanisms whose origins are not yet well understood. Indeed, similar observations were made over 20 years ago in certain uncoated materials (such as SiC) using conventional SEM (Sawyer and Page, 1978). Aspects of these charge contrast imaging (CCI) phenomena are further documented here in a series of ESEM experiments on polished cross sections of uncoated travertine calcite. What is “old” is the fact that these contrasts have been reported on several occasions. What is “new” is the observation that these unusual contrasts are more readily studied and, in some cases, have been found in a wider range of materials using ESEM.

Advances in Environmental Scanning Electron Microscopy: Semiconductor/Thin Fim Applications, Cathodoluminescence (CL) Spectroscopy, and Detector Quantum Efficiency (DQE) Comparisons.

1999 ◽  
Vol 5 (S2) ◽  
pp. 278-279
Author(s):  
Brendan J. Griffin ◽  
James R. Browne ◽  
Dominique Drouin ◽  
David Scharf
Keyword(s):  
Film Growth ◽  
Environmental Scanning Electron Microscopy ◽  
Variable Pressure ◽  
Environmental Scanning ◽  
Contrast Imaging ◽  
Initial Examination ◽  
Near Surface ◽  
Diamond Surfaces ◽  
Surface Contaminants ◽  
Scanning Electron

Charge Contrast Imaging (CCI) in the environmental scanning electron microscope (ESEM) has rapidly evolved to an important imaging technique for a range of materials. The investigation of the applicability of CCI to the examination of semiconductor and thin film (MCT) samples and devices has been highly successful. Dopant concentration and depth can be differentiated, as has been noted for variable pressure SEM. Quantification of concentration remains difficult due to the complexity of variables controlling CCI but should be achievable in the near future. The extreme sensitivity to surface contaminants previously noted on polished diamond surfaces is also seen on silicon. Monte Carlo modelling of this contrast indicates, for the examined materials, an information depth of a few nanometres for CCI, whilst using 30kV accelerating voltage. The modelling shows that CCI is capable of routine detection of contaminant layers on silicon at the nanometre scale. These results also provide the first data confirming initial suggestions that CCI is derived from the near-surface regions of the sample.CCI examination of mercury cadmium telluride (MCT) devices has also provided images with new detail. This detail is currently being interpreted. Initial examination suggests an influence of the substrate on film growth (figure 1). Unusual corner structures are visible around the mask region.

Environmental Scanning Electron Microscopy as a Tool to Study Shrinkage Microcracks in Cement-Based Materials

1999 ◽  
Vol 589 ◽  
Author(s):  
J. Bisschop ◽  
J.G.M. Van Mier
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Relative Humidity ◽  
Cross Sections ◽  
Preparation Method ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Sample Preparation Method ◽  
Cement Based Materials ◽  
Scanning Electron

AbstractIn this paper a method is described to observe shrinkage microcracks on ‘wet’ specimen cross-sections of cement-based materials with Environmental Scanning Electron Microscopy (ESEM). A sample cooling device which can be used in the ESEM chamber was built to control the relative humidity above a microscope sample. The accuracy of measuring relative humidity is determined to be 5% at a sample temperature of 3°C. A microscope sample preparation method and a pump-down sequence of the ESEM-chamber, both without any drying of the sample, are described. Preliminary results show that in the studied mortar the visibility of shrinkage microcracks on a ‘wet’ specimen cross-section is low due to closure of microcracks by swelling of the cement paste.

High-Resolution, Low-Voltage SEM of Cell Wall Regeneration of Yeast Shizosaccharomyces Pombe Protoplasts

1988 ◽  
Vol 46 ◽  
pp. 208-211
Author(s):  
M. Osumi ◽  
N. Yamada ◽  
T. Nagatani
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Low Voltage ◽  
Cell Wall Regeneration ◽  
The Past ◽  
The Poor ◽  
Probe Size ◽  
Beam Damage ◽  
Biological Field ◽  
Scanning Electron

Even though many early workers had suggested the use of lower voltages to increase topographic contrast and to reduce specimen charging and beam damage, we did not usually operate in the conventional scanning electron microscope at low voltage because of the poor resolution, especially of bioligical specimens. However, the development of the “in-lens” field emission scanning electron microscope (FESEM) has led to marked inprovement in resolution, especially in the range of 1-5 kV, within the past year. The probe size has been cumulated to be 0.7nm in diameter at 30kV and about 3nm at 1kV. We have been trying to develop techniques to use this in-lens FESEM at low voltage (LVSEM) for direct observation of totally uncoated biological specimens and have developed the LVSEM method for the biological field.

Linewidth measurement using the low voltage SEM

1986 ◽  
Vol 44 ◽  
pp. 652-653
Author(s):  
M.G. Rosenfield
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Secondary Electron ◽  
Low Voltage ◽  
Fabrication Process ◽  
Critical Dimensions ◽  
Linewidth Measurement ◽  
Threshold Technique ◽  
Scanning Electron

Minimum feature sizes in experimental integrated circuits are approaching 0.5 μm and below. During the fabrication process it is usually necessary to be able to non-destructively measure the critical dimensions in resist and after the various process steps. This can be accomplished using the low voltage SEM. Submicron linewidth measurement is typically done by manually measuring the SEM micrographs. Since it is desirable to make as many measurements as possible in the shortest period of time, it is important that this technique be automated.Linewidth measurement using the scanning electron microscope is not well understood. The basic intent is to measure the size of a structure from the secondary electron signal generated by that structure. Thus, it is important to understand how the actual dimension of the line being measured relates to the secondary electron signal. Since different features generate different signals, the same method of relating linewidth to signal cannot be used. For example, the peak to peak method may be used to accurately measure the linewidth of an isolated resist line; but, a threshold technique may be required for an isolated space in resist.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

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