scholarly journals Amorphization and the Effect of Implanted Ions in Sic

1994 ◽  
Vol 373 ◽  
Author(s):  
L. L. Snead ◽  
S. J. Zinkle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Volume Change ◽  
Room Temperature ◽  
Threshold Dose ◽  
The Other ◽  
Ion Chemistry ◽  
Transmission Electron ◽  
Ion Species

AbstractThe effects of implanted ion chemistry and displacement damage on the amorphization threshold dose of SiC were studied using cross-section transmission electron microscopy. Room temperature as well as 200 and 400°C irradiations were carried out with 3.6 MeV Fe, 1.8 MeV Cl, 1 MeV He or 0.56 MeV Si ions. The room temperature amorphization threshold dose in irradiated regions well separated from the implanted ions was found to range from 0.3 to 0.5 dpa for the four different ion species. The threshold dose for amorphization in the He, Si and Fe ion-implanted regions was also σ0.3 to 0.5 dpa. On the other hand, the amorphization threshold in the Climplanted region was only about 0.1 dpa. The volume change associated with amorphization was σ17&. No evidence for amorphization was obtained in specimens irradiated at 200 or 400°C.

Extension, Closure and Conversion of In-Grown Stacking Faults in 4H-SiC Epilayers

2018 ◽  
Vol 924 ◽  
pp. 155-159
Author(s):  
Zhe Li ◽  
Tao Ju ◽  
Bao Shun Zhang ◽  
Xuan Zhang ◽  
Li Guo Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Room Temperature ◽  
Stacking Faults ◽  
Step Flow ◽  
Transmission Electron ◽  
Step Flow Growth ◽  
Koh Etching ◽  
Low Temperature Photoluminescence

In-grown stacking faults (IGSFs) generated in 4H-SiC epilayers were characterized. Melted KOH etching, room-temperature cathodoluminescence, low-temperature photoluminescence and cross-section transmission electron microscopy was conducted to investigate the propagation of the IGSFs in the down-stream region of a 3C inclusion. It was found that the SFs could extend, close and convert during the epitaxial growth. The origin of these IGSFs were attributed to the interference introduced by the 3C inclusion to the step-flow growth, and the propagating behaviors of these IGSFs were discussed.

Ion implantation in β-SiC: Effect of channeling direction and critical energy for amorphization

1988 ◽  
Vol 3 (2) ◽  
pp. 321-328 ◽  
Author(s):  
J. A. Edmond ◽  
R. F. Davis ◽  
S. P. Withrow ◽  
K. L. More
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Computer Program ◽  
Liquid Nitrogen ◽  
Cross Section ◽  
Damage Accumulation ◽  
Room Temperature ◽  
Critical Energy ◽  
Implantation Dose ◽  
Transmission Electron

Damage in single-crystal β-SiC(100) as a result of ion bombardment has been studied using Rutherford backscattering/channeling and cross-section transmission electron microscopy. Samples were implanted with Al (130 keV) and Si (87 keV) with doses between 4 and 20 × 1014 cm−2 at liquid nitrogen and room temperatures. Backscattering spectra for He+ channeling as a function of implantation dose were initially obtained in the [110] direction to determine damage accumulation. However, the backscattered yield along this direction was shown to be enhanced as a result of uniaxial implantation-induced strain along [100]. Spectra obtained by channeling along this latter direction were used along with the computer program TRIM to calculate the critical energy for amorphization. The results for amorphization of β-SiC at liquid nitrogen and room temperature are ∼ 14.5 eV/atom and ∼ 22.5 eV/atom, respectively.

Effect of SPS processing temperature on the microstructure and properties of a Ti49Al47Cr2Nb2 alloy

2006 ◽  
Vol 980 ◽  
Author(s):  
Alain Couret ◽  
Guy Molénat ◽  
Jean Galy ◽  
Marc Thomas
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
The Other ◽  
Processing Temperature ◽  
Post Mortem ◽  
Tial Alloys ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Limited Creep

AbstractThe sintering of TiAl alloys by the Spar Plasma Sintering (SPS) technique is investigated in the present paper. Compactions are conducted between 1100°C and 1225°C on a Ti49Al47Cr2Nb2 powder. Single phased and lamellar microstructures are generated at low and high temperatures, respectively. The former exhibits enhanced tensile properties at room temperature but at the expense of a limited creep resistance. On the other hand, the latter suffers from a poor ductility.The deformation systems which are activated are determined by post-mortem transmission electron microscopy. The behavior of the single phased-alloy is analyzed in terms of the Hall-Petch law.

Microstructures at the Interface Between a-Axis Oriented YBa2Cu3O7−x and NdGaO3(110) Substrate

1992 ◽  
Vol 275 ◽  
Author(s):  
Hiromi Takahashi ◽  
Norio Homma ◽  
Satoru Okayama ◽  
Tadataka Morishita
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tensile Stress ◽  
Cross Section ◽  
Lattice Mismatch ◽  
The Other ◽  
Oriented Film ◽  
Transmission Electron ◽  
Small Lattice ◽  
Orientational Relationship

ABSTRACTThe interface between an a-axis oriented YBa2Cu3O7-x film and a NdGaO3(110) substrate has been investigated by cross-section transmission electron microscopy (TEM). The orientational relationship between the a-axis oriented film and substrate is YBa2Cu3O7-x[001] / NdGaO3[001]. This preferentially c-axis aligned direction of the YBa2Cu3O7-x film would be caused by a very small lattice mismatch (0.1%) between b(=a) lattice constant of YBa2Cu3O7-x and of the pseudo-cubic sub-lattices in NdGaO3 at a substrate temperature of 750°C. Two kinds of imperfections have been observed in the crystal lattice of YBa2Cu3O7-x near the interface; One is the deviation of YBa2Cu3O7-x [301] from NdGaO3 [111]. The other type is pair dislocations with a positive and negative Burgers vectors in the YBa2Cu3O7-x (103) planes. These two kinds of defects at the interface would be act to reduce the tensile stress within a distance of about l.lnm from the substrate interface.

Scanning and Transmission Electron Microscopy of Human Red Blood Cells

1969 ◽  
Vol 27 ◽  
pp. 44-45
Author(s):  
A.J. Tousimis ◽  
T.R. Padden
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Blood Cells ◽  
Room Temperature ◽  
Type Specimen ◽  
New Combination ◽  
Human Red Blood Cells ◽  
Transmission Electron ◽  
Microscope Slides ◽  
Scanning Electron

The size, shape and surface morphology of human erythrocytes (RBC) were examined by scanning electron microscopy (SEM), of the fixed material directly and by transmission electron microscopy (TEM) of surface replicas to compare the relative merits of these two observational procedures for this type specimen.A sample of human blood was fixed in glutaraldehyde and washed in distilled water by centrifugation. The washed RBC's were spread on freshly cleaved mica and on aluminum coated microscope slides and then air dried at room temperature. The SEM specimens were rotary coated with 150Å of 60:40- gold:palladium alloy in a vacuum evaporator using a new combination spinning and tilting device. The TEM specimens were preshadowed with platinum and then rotary coated with carbon in the same device. After stripping the RBC-Pt-C composite film, the RBC's were dissolved in 2.5N HNO3 followed by 0.2N NaOH leaving the preshadowed surface replicas showing positive topography.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

The use of an energy-filtering electron microscope to reduce chromatic aberration in images of thick biological specimens

1986 ◽  
Vol 44 ◽  
pp. 88-91
Author(s):  
L. D. Peachey ◽  
J. P. Heath ◽  
G. Lamprecht
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Cross Section ◽  
Electron Scattering ◽  
Chromatic Aberration ◽  
Image Resolution ◽  
Incident Electron Energy ◽  
Energy Filtering ◽  
Transmission Electron

Biological specimens of cells and tissues generally are considerably thicker than ideal for high resolution transmission electron microscopy. Actual image resolution achieved is limited by chromatic aberration in the image forming electron lenses combined with significant energy loss in the electron beam due to inelastic scattering in the specimen. Increased accelerating voltages (HVEM, IVEM) have been used to reduce the adverse effects of chromatic aberration by decreasing the electron scattering cross-section of the elements in the specimen and by increasing the incident electron energy.

A crystallographic analysis of the CoSi/Si(111) interface using Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 574-575
Author(s):  
A.C. Daykin ◽  
C.J. Kiely ◽  
R.C. Pond ◽  
J.L. Batstone
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Structure ◽  
Room Temperature ◽  
Theoretical Method ◽  
Crystallographic Analysis ◽  
Si Substrate ◽  
Transmission Electron ◽  
Theoretical Predictions

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.

Synthesis and TEM study of Ag–In–(Eu, Ce) ternary approximants

2009 ◽  
Vol 224 (1-2) ◽  
Author(s):  
Kazue Nishimoto ◽  
Miki Muraki ◽  
Ryuji Tamura
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Transmission Electron

AbstractTernary Ag–In–(Eu, Ce) 1/1 approximants are synthesized and their structures are studied by transmission electron microscopy (TEM). For both the approximants, superlattice spots are clearly observed at room temperature, and the superstructures of the Ag–In–(Eu, Ce) approximants are found to be similar to those of Cd

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