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.

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.

Studies of c-Axis Threading Screw Dislocations in Hexagonal SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Yi Chen ◽  
Xianrong Huang ◽  
Ning Zhang ◽  
Govindhan Dhanaraj ◽  
Edward Sanchez ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Grazing Incidence ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
X Ray ◽  
Back Reflection ◽  
Partial Dislocations ◽  
Ray Tracing Simulation ◽  
Vector Magnitude

ABSTRACTIn our study, closed-core threading screw dislocations and micropipes were studied using synchrotron x-ray topography of various geometries. The Burgers vector magnitude of TSDs can be quantitatively determined from their dimensions in back-reflection x-ray topography, based on ray-tracing simulation and this has been verified by the images of elementary TSDs. Dislocation senses of closed-core threading screw dislocations and micropipes can be revealed by grazing-incidence x-ray topography. The threading screw dislocations can be converted into Frank partial dislocations on the basal planes and this has been confirmed by transmission synchrotron x-ray topography.

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.

scholarly journals An experimental study of diffuse X-ray reflexion by single crystals

1941 ◽  
Vol 179 (976) ◽  
pp. 8-50 ◽  
Keyword(s):  
Experimental Study ◽  
Single Crystals ◽  
Reciprocal Lattice ◽  
Organic Crystals ◽  
X Rays ◽  
X Ray ◽  
The Difference ◽  
Lattice Planes ◽  
Diffuse Spot

A historical introduction outlines the development of experimental and theoretical interest in the diffuse diffraction of X-rays by single crystals. The present experimental study, illustrated by numerous photographs, has consisted in taking Laue, oscillation and rotation photographs, in many different orientations, of inorganic and organic crystals belonging to various systems, using Cu, Mo and Ag radiations, unfiltered, filtered or monochromatized. Rules are laid down for the indexing of diffuse spots and for the determination of the conditions under which such spots appear. Attention is drawn to the presence of non-radial streaks and to the difference in origin of these and of the more usual radial streaks. The relations of the intensity, shape, size, position and persistence of the diffuse spots to the nature, structure, perfection, orientation and temperature of the crystal examined, to the radiation used and to the conditions of photography, are considered in some detail. The use of diffuse spot patterns as a subsidiary method of crystal structure determination is emphasized. It is pointed out that in reciprocal space each reflecting lattice point is surrounded by a region of diffuse scattering, whose physical significance is open to various theoretical interpretations. These diffusely reflecting regions are not, in general, spherical, but are extended along reciprocal lattice planes and axes.

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