A Descriptive in vitro Electron Microscopic Study of Acidic Fluoride-Treated Enamel: Potential Anti-Erosion Effects

2015 ◽  
Vol 49 (6) ◽  
pp. 618-625 ◽  
Author(s):  
Carl Hjortsjö ◽  
Alix Young ◽  
Andreas Kiesow ◽  
Andreas Cismak ◽  
Lutz Berthold ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Surface Film ◽  
Ion Beam ◽  
Dental Enamel ◽  
Surface Films ◽  
Electron Microscopic ◽  
Human Teeth ◽  
Cross Sectional

This study aimed to investigate the surface zones of acidic fluoride-treated enamel. Human teeth were each divided into three or four enamel specimens that were treated for 10 min with solutions of 0.2 and 0.4% HF (pH 3.09 and 2.94), 1.74% SnF2 (pH 2.9), 0.68% TiF4 (pH 1.6) and 0.84% NaF (pH 4.5). Untreated specimens functioned as negative controls. The microstructure and elemental composition of the surface zones were studied by scanning electron microscopy/energy-dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and nanospot-EDX following cross-sectional preparation using focused ion beam technology. TEM/EDX analyses of NaF-treated specimens showed a 500-nm-thick closed surface film containing 20-40 at% (atomic percent) F. HF-treated specimens had a distinct surface film 200-600 nm thick (dense, not globular) containing 45-47 at% F. TiF4-treated specimens had a surface film of 200-300 nm in thickness containing 8-11 at% Ti but no detectable fluoride. SnF2-treated specimens had a modified surface enamel layer varying in thickness from 200 to 800 nm with an inhomogeneous distribution of Sn. Local spots were detected with as high as 8 at% Sn (30 wt%, weight percent). The results suggest that the reaction mechanisms of SnF2 and TiF4 solutions with dental enamel differ from those occurring after enamel exposure to acidulated NaF and HF solutions. While the HF and NaF treatments resulted in the formation of CaF2-like material as shown by EDX, no significant surface fluoridation was found for SnF2 and TiF4 solutions within the TEM/EDX detection limits. These results suggest that the erosion-protective mechanisms of these latter compounds probably relate more to the formation of hardly soluble and acid-resistant reaction surface films and less to surface fluoride incorporation.

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

Effect of Whole Saliva Components on Enamel Demineralization In Vitro

1993 ◽  
Vol 4 (3) ◽  
pp. 357-362 ◽  
Author(s):  
J.D.B. Featherstone ◽  
J.M. Behrman ◽  
J.E. Bell
Keyword(s):  
Dental Enamel ◽  
Acid Resistance ◽  
Human Teeth ◽  
Cross Sectional ◽  
Basic Proteins ◽  
Enamel Demineralization ◽  
Whole Saliva ◽  
Flow Through ◽  
Mineral Loss

The aim of the present study was to use an in vitro enamel demineralization model (1) to confirm that whole saliva pretreatment conferred acid resistance to dental enamel and (2) to determine whether this phenomenon was attributable to specific salivary proteins, minerals, lipids, or some combination of these. Crowns of human teeth, each with one exposed window, were prepared in groups of ten. They were each pretreated by immersion individually in 4 ml of either (1) clarified whole saliva for 18, 72, or 168 h, (2) dialyzed saliva (3500 MWCO membrane), (3) the "flow-through" fraction from a DEAE separation of whole saliva (neutral and basic proteins), (4) the "eluted" fraction of a DEAE separation of whole saliva (anionic proteins), or (5) a combination of salivary lipids and the DEAE "flow-through" fraction of whole saliva (neutral and basic proteins). Control groups were group 6 with no pretreatment, group 7 pretreated for 168 h in a borate buffer (5 mmol/1), and group 8 pretreated in a mineral solution containing calcium (0.7 mmol/1) and phosphate (2.6 mmol/1). The crowns were then demineralized for 7 d in vitro (0.1 mol/1 acetate, 1 mmol/l Ca and phosphate, pH 5.0) to produce artificial caries-like lesions. Lesions were assessed by cross-sectional microhardness profiles, and mineral loss (AZ, μm x vol% mineral) calculated. Mineral loss (AZ) values decreased linearly with the square root of time of pretreatment by whole saliva, confirming a time-dependent protective effect of salivary pellicle against demineralization of enamel. Pretreatments (168 h) by whole saliva (group 1), dialyzed saliva (group 2), and lipid/'flow through" proteins (group 5) gave equivalent protection (approximately 55%). However, no protection was provided by DEAE-separated protein fractions (no lipid present) or by the mineral alone. The protection of surface enamel against demineralization appears to be given by a combination of specifically adsorbed salivary lipids and proteins.

Scanning Electron Microscopy Observation of Interface Between Single Neurons and Conductive Surfaces

2016 ◽  
Vol 16 (4) ◽  
pp. 3383-3387 ◽  
Author(s):  
Toichiro Goto ◽  
Nahoko Kasai ◽  
Rick Lu ◽  
Roxana Filip ◽  
Koji Sumitomo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Indium Tin Oxide ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Single Neurons ◽  
Sem Images ◽  
Cross Sectional ◽  
Integrated Devices ◽  
Scanning Electron

Interfaces between single neurons and conductive substrates were investigated using focused ion beam (FIB) milling and subsequent scanning electron microscopy (SEM) observation. The interfaces play an important role in controlling neuronal growth when we fabricate neuron-nanostructure integrated devices. Cross sectional images of cultivated neurons obtained with an FIB/SEM dual system show the clear affinity of the neurons for the substrates. Very few neurons attached themselves to indium tin oxide (ITO) and this repulsion yielded a wide interspace at the neuron-ITO interface. A neuron-gold interface exhibited partial adhesion. On the other hand, a neuron-titanium interface showed good adhesion and small interspaces were observed. These results are consistent with an assessment made using fluorescence microscopy. We expect the much higher spatial resolution of SEM images to provide us with more detailed information. Our study shows that the interface between a single neuron and a substrate offers useful information as regards improving surface properties and establishing neuron-nanostructure integrated devices.

Fabrication of Planar and Cross-Sectional TEM Specimens Using a Focused Ion Beam

1990 ◽  
Vol 199 ◽  
Author(s):  
R. J. Young ◽  
E. C. G. Kirk ◽  
D. A. Williams ◽  
H. Ahmed
Keyword(s):  
Electron Microscopy ◽  
Integrated Circuits ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cross Sectional ◽  
Transmission Electron ◽  
A New Technique ◽  
Sectional Analysis ◽  
Selection Of ◽  
Better Than

ABSTRACTA new technique using a focused ion beam has been developed for the fabrication of transmission electron microscopy specimens in pre-selected regions. The method has been proven in the fabrication of both cross-sectional and planar specimens, with no induced artefacts. The lateral accuracy achievable in the selection of an area for cross-sectional analysis is better than one micrometre. The technique has been applied to a number of silicon and III-V based integrated circuits, and is expected to be suitable for many other materials and structures.

Two-Dimensional Damage Distributions Induced by Localized Ion Implantations

1992 ◽  
Vol 283 ◽  
Author(s):  
M. M. Faye ◽  
L. Laanab ◽  
J. Beauvillain ◽  
A. Claverie ◽  
C. Vieu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Quantum Nanostructures ◽  
Transmission Electron ◽  
Ion Beam Implantation ◽  
General Method

ABSTRACTA general method is presented for calculating the spatial distribution of damage generated by localized implantation in semiconductors. Implantation through masks and focused ion beam implantation in GaAs are simulated and compared to cross-sectional transmission electron microscopy observations. An excellent agreement is obtained when a depth-dependent lateral straggle is considered. Arbitrarily shaped mask edges and different compositions for the mask and the substrate are included in the calculations as well as realistic current profiles of the ion spot in the case of focused ion beam implantations. Simulations and experiments clearly demonstrate the potential application of localized implantations to fabricate lateral quantum nanostructures.

Failure Analysis of Tungsten Stud Defect from the CMP Process

2000 ◽  
Author(s):  
K. Takagi ◽  
Y. Kohno ◽  
S. Nukii
Keyword(s):  
Electron Microscopy ◽  
Failure Analysis ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Electrical Characterization ◽  
Open Circuit ◽  
Physical Analysis ◽  
Metal Line ◽  
Cross Sectional ◽  
Defect Isolation

Abstract This paper describes a failure analysis that effectively combined multiple analytic techniques to find the cause of I/O leakage in a flawed chip produced for an OEM (Original Equipment Manufacturer) product. Internal probing was initially used for defect isolation and a Tungsten (W) stud open circuit flaw was isolated by electrical characterization with internal probing. SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy, and FE-AES (Field Emission Auger Electron Spectroscopy) analysis with FIB (Focused Ion Beam) preparation were used for physical analysis. Cross-sectional SEM and TEM observations showed a gap with foreign material (FM) between the bottom of the metal line and the top of the W stud, possibly from the W CMP (chemical mechanical polish) process. FE-AES is effective for the analysis of light materials and their chemical composition, so a flat milling FIB process was used to prepare a cross-section for FE-AES analysis of the FM and the interfaces of the open defect. The spectra showed that the FM was traceable to the W CMP process. From these analytical results and problem reproduction experiments in the W CMP process on the manufacturing line, the failure mechanism was identified.

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