Synchrotron White Radiation X-Ray Topographic Investigation of Dislocation Configurations Developed in Indium Antimonide Single Crystals by Plastic Bending

1993 ◽  
Vol 307 ◽  
Author(s):  
Jun Wu ◽  
M. Dudley
Keyword(s):  
Single Crystals ◽  
Indium Antimonide ◽  
Plastic Behavior ◽  
Dislocation Loops ◽  
Screw Dislocations ◽  
X Ray ◽  
Three Point Bending ◽  
Brittle To Ductile Transition ◽  
Plastic Deformation Process ◽  
The Relationship

ABSTRACTSynchrotron white beam x-ray topography has been used to study dislocation configurations induced in InSb single crystals by three point bending at temperatures above the brittle to ductile transition point. Semi-hexagonal dislocation loops with one long screw segment and two outcropping 60° segments, single 60° B(g) dislocation kinks on screw dislocations, and screw dislocation dipoles were observed. The relationship between these observed defect structures and the mobilities of A(g), B(g), and screw dislocations in InSb, which appear to control the plastic behavior of crystals with the sphalerite structure, is discussed. Dislocation interactions and their role in the plastic deformation process are also addressed.

Generation of Defects and Strain by Ion Implantation in Ge (100) Single Crystals, and in Pseudomorphic GexSi1-x Films Grown on Si (100)

1992 ◽  
Vol 262 ◽  
Author(s):  
D. Y. C. Lie ◽  
A. Vantomme ◽  
F. Eisen ◽  
M. -A. Nicolet ◽  
V. Arbet-Engels ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Single Crystals ◽  
Room Temperature ◽  
Defect Concentration ◽  
Double Crystal ◽  
X Ray ◽  
Positive Strain ◽  
Independent Coefficient ◽  
The Relationship ◽  
Si Ion Implantation

ABSTRACTWe have studied the damage and strain produced in Ge (100) single crystals by implantation of various doses of 300 keV 28Si ions at room temperature. The analyzing tools were x-ray double-crystal diffractometry, and MeV 4He channeling spectrometry. The damage induced by implantation produces positive strain in Ge (100). The maximum perpendicular strain and maximum defect concentration rise nonlinearly with increasing dose. These quantities are linearly related with a dose-independent coefficient of ∼ 0.013 for Ge (100) single crystals implanted at room temperature. The results are compared with those available for Si (100) self-implantation. We have also monitored the strain and defects generated in pseudomorphic Ge0.1Si0.9/Si (100) films induced by room temperature 28Si ion implantation. It is found that the relationship between the strain and defect concentration induced by ion implantation is no longer a simple linear one.

Characterization of Defect Structures in SiC Single Crystals Using Synchrotron X-Ray Topography

1993 ◽  
Vol 307 ◽  
Author(s):  
S. Wang ◽  
M. Dudley ◽  
C. Carter ◽  
D. Asbury ◽  
C. Fazit
Keyword(s):  
Detailed Analysis ◽  
Single Crystals ◽  
Basal Plane ◽  
Defect Structures ◽  
Dislocation Generation ◽  
Screw Dislocations ◽  
X Ray ◽  
White Beam

ABSTRACTSynchrotron white beam X-ray topography has been used to characterize defect structures in 6H-SiC wafers grown on (0001) seeds. Two major types of defects are observed: super screw dislocations approximately perpendicular to the basal plane and dislocation networks lying in the basal plane. The super screw dislocations, which have open cores, are growth dislocations. These dislocations act as sources and/or sinks for the glide dislocation networks. Detailed analysis and discussion of dislocation generation phenomena and Burgers vectors will be presented.

Synchrotron White Beam Topography Studies of Screw Dislocations in 6H-Sic Single Crystals

1994 ◽  
Vol 375 ◽  
Author(s):  
S. Wang ◽  
M. Dudley ◽  
C. H. Carter ◽  
V. F. Tsvetkov ◽  
C. Fazi
Keyword(s):  
Single Crystals ◽  
Structural Defects ◽  
Device Performance ◽  
Topographic Image ◽  
X Ray Diffraction ◽  
Screw Dislocations ◽  
X Ray ◽  
White Beam ◽  
Line Defects ◽  
Kinematical Theory

AbstractSynchrotron white beam X-ray topography, along with optical microscopy and scanning electron microscopy, has been used to characterize structural defects which are potentially detrimental to device performance in PVT 6H-SiC single crystals. Line defects running along the [0001] axis, known as “micropipes”, were studied extensively. Detailed analysis of topographic image contrast associated with “micropipes”, based on the kinematical theory of X-ray diffraction, established that the so-called “micropipes” are screw dislocations with large Burgers vectors.

Interaction of 6H-Type Stacking Faults with Threading Screw Dislocations in PVT-Grown 4H-SiC Single Crystals

2012 ◽  
Vol 717-720 ◽  
pp. 411-414
Author(s):  
Shinya Sato ◽  
T. Fujimoto ◽  
H. Tsuge ◽  
M. Katsuno ◽  
W. Ohashi
Keyword(s):  
High Resolution ◽  
Single Crystals ◽  
Room Temperature ◽  
Stacking Faults ◽  
Screw Dislocations ◽  
X Ray

6H-type stacking faults (SFs) observed in PVT-grown 4H-SiC ingle crystals were investigated using Photoluminescence (PL) microscopy at room temperature. Structural analyses using high resolution X-ray topography have revealed that there exist no (n=4, 8) component in Burger’s vectors of the 6H-type SFs we observed, strongly suggesting that the 6H-type SFs are constructed either by insertions of very thin 6H-type foreign polytype inclusions or by successive repetitions of Shockley-type in-plane glides.

The Effect of Oxygen on the Brittle-to-Ductile Transition in Silicon Single Crystals

2010 ◽  
Vol 654-656 ◽  
pp. 1299-1302
Author(s):  
Youn Jeong Hong ◽  
Masaki Tanaka ◽  
Kenji Higashida
Keyword(s):  
Single Crystals ◽  
Silicon Crystal ◽  
Dislocation Mobility ◽  
Dislocation Glide ◽  
Three Point Bending ◽  
Brittle To Ductile Transition ◽  
Silicon Crystals ◽  
Apparent Fracture Toughness ◽  
The Difference ◽  
Effect Of Oxygen

The brittle-to-ductile transition (BDT) in Czochralski (CZ) grown silicon single crystals and floating-zone (FZ) grown silicon single crystals was investigated by three-point bending. The temperature dependence of the apparent fracture toughness was measured in three different cross-head speeds. It was found that the BDT temperature in the CZ silicon crystal was higher than that in FZ silicon crystal, suggesting that the solute oxygen decreases dislocation mobility. However, the activation energies obtained from the strain rate dependence of the BDT temperatures were nearly the same in both the CZ and FZ silicon crystals, indicating that the dislocation mobility is not influenced by the solute oxygen. In this paper, the origin of the difference in the BDT temperature is discussed, focusing the role of the solute oxygen on the dislocation glide.

Structural Transformation from TSDs to Frank-Type Stacking Faults by Giant Bunched Steps in PVT-Grown 4H-SiC Single Crystals

2016 ◽  
Vol 858 ◽  
pp. 97-100 ◽  
Author(s):  
Shinya Sato ◽  
Tatsuo Fujimoto ◽  
Hiroshi Tsuge ◽  
Masakazu Katsuno ◽  
Masashi Nakabayashi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Single Crystals ◽  
Structural Transformation ◽  
Stacking Faults ◽  
Stacking Sequence ◽  
Screw Dislocations ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Stacking Structure

Structural transformation from threading screw dislocations (TSDs) to stacking faults (SFs) has been investigated for PVT-grown 4H-SiC single crystals using X-ray topography and transmission electron microscopy (TEM). The transformation of TSDs is induced by the structural interference with bunched surface macrosteps over 100 nm in height. The stacking sequence of a SF was determined to be (433) in Zadanov's notation by using high-resolution TEM. Our detailed analyses revealed that the (433) stacking structure can be constructed by a combination of five faults including both four Frank type faults and one Shockley type fault.

Effects of pressure, temperature, and grain size on the kinetics of the calcite → aragonite transformation

1979 ◽  
Vol 16 (7) ◽  
pp. 1402-1418 ◽  
Author(s):  
N. S. Brar ◽  
H. H. Schloessin
Keyword(s):  
Grain Size ◽  
Single Crystals ◽  
Relative Increase ◽  
Surprising Result ◽  
X Ray ◽  
Mass Fractions ◽  
Deviatoric Stresses ◽  
The Relationship ◽  
Kinetics Of ◽  
Iceland Spar

Single crystals and polycrystalline samples of transparent calcite (Iceland spar) were used to investigate the effects of pressure (p), temperature (T), pressure beyond an accepted equilibrium value (Δp), and grain size (D) on the kinetics of the calcite–aragonite transformation. Transformed mass fractions x(t), produced after different times of exposure to constant pressure ranging from 14 to 25 kbar (1.4 to 2.5 GPa) and constant temperature from 300 to 600 °C, were determined from integrated X-ray peak intensities of the (012), (021), and (111) reflections of aragonite. Values for the rale constant K and the exponent n characterizing the transformation were computed from the x(t) data using Cahn's nucleation and growth model for solid–solid transformations. At 17 kbar(1.7 GPa), K(s−1) increases from 2.00 × 10−5 at 300 °C to 1.39 × 10−3 at 600 °C. The exponent n, of the order of 1, mostly <1, indicates that the nucleation stage is terminated rapidly by site saturation and that most of the transformation takes place thereafter by growth as expected from theory. For single crystals the relationship between x(t) and Δp, for a period of 1 hour is almost linear. At 600 °C the relative increase of x(t) amounts to 0.1 kbar−1 (1 × 107 Pa−1). For a given time, x increases nearly exponentially with T. The apparent activation energy for the transformation, at 17 kbar (1.7 GPa), is 16 kcal mol−1. For polycrystals x(t) decreases as [Formula: see text]. This somewhat surprising result may be related to deviatoric stresses and stress concentration by the already transformed volume fractions, which act as misfitting, ellipsoidal, inclusions.

Origin Analyses of Trapezoid-Shape Defects in 4-Deg.-off 4H-SiC Epitaxial Wafers by Synchrotron X-Ray Topography

2014 ◽  
Vol 778-780 ◽  
pp. 374-377 ◽  
Author(s):  
Tamotsu Yamashita ◽  
Hirofumi Matsuhata ◽  
Yoshihiko Miyasaka ◽  
Kenji Momose ◽  
Takayuki Sato ◽  
...  
Keyword(s):  
Basal Plane ◽  
Surface Defects ◽  
Epitaxial Film ◽  
Negative Impact ◽  
Film Surface ◽  
Dislocation Loops ◽  
Screw Dislocations ◽  
X Ray ◽  
Mos Devices ◽  
Edge Dislocations

The trapezoid-shape defects are one of the most common surface defects on current 4H-SiC epitaxial film surface since they give rise negative impact for MOS-devices. We have investigated structures and origins of the defects. It is discovered that the possible origins of the trapezoid-shape defects are basal plane dislocations (BPDs), threading edge dislocations (TEDs), threading screw dislocations (TSDs),and the short dislocation loops introduced under scratches.

Determination of Burgers Vector of Screw Dislocations in 6H-SiC Single Crystals by Synchrotron White Beam X-Ray Topography

1996 ◽  
Vol 437 ◽  
Author(s):  
W. Si ◽  
M. Dudley ◽  
C. Carter ◽  
R. Glass ◽  
V. Tsvetkov
Keyword(s):  
Single Crystals ◽  
Dislocation Core ◽  
Line Defect ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
X Ray ◽  
White Beam ◽  
Lattice Planes ◽  
Vector Magnitude

AbstractIndividual screw dislocations along the [0001] axis in 6H-SiC single crystals have been characterized by means of Synchrotron White Beam X-ray Topography (SWBXT). The magnitude of the Burgers vector was determined from: (1) the diameter of circular diffraction-contrast images of dislocations in back-reflection topographs, (2) the width of bi-modal images associated with screw dislocations in transmission topographs, (3) the magnitude of the tilt of the lattice planes on both sides of dislocation core in projection topographs, and (4) also the magnitude of the tilt of the lattice planes in section topographs. All of the four methods showed reasonable consistency. The sense of the Burgers vector can also be deduced from the abovementioned tilt of the lattice planes. Results revealed that in 6H-SiC a variety of screw dislocations can be found with Burgers vector magnitude ranging from 1c to 7c (c is the lattice constant along [0001] axis). This work demonstrates that SWBXT can be used as a quantitative technique for detailed analyses of line defect configurations.

Multilayers: A Research Tool for Mechanical Property and Alloy Phase Stability Investigations

MRS Bulletin ◽  
1987 ◽  
Vol 12 (7) ◽  
pp. 80-83
Author(s):  
A.F. Jankowski
Keyword(s):  
Materials Science ◽  
Protective Coatings ◽  
Surface Hardness ◽  
Optical Devices ◽  
Multilayer Structures ◽  
Plastic Behavior ◽  
X Ray ◽  
Strained Layer Superlattices ◽  
The Relationship

The magic of multilayer structures — comprised of a regular repeating pattern of alternating layers that vary in thickness from less than 1 nm to more than several micrometers — is present today in nearly every facet of materials science.A technological gamut of issues has been approached through the use of multilayer structures. Material systems have been routinely investigated, ranging from simple binary through complex quaternary and including nearly every element of the periodic table. Applications include thin-film semiconductor devices in the form of strained-layer superlattices; protective coatings for improved surface hardness and wear resistance of conventional alloys (tribology); and reflective and transmissive x-ray optical devices. Multilayer structures have also provided an experimental means to investigate the interdiffusion and stability of alloy phases; the relationship between the presence, lack, or variations of crystallinity with magnetism (and most recently superconductivity); and the role of interfaces in adhesion and elastic/plastic behavior.

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