Computer Aided Synchrotron White Beam X-Ray Topographic Analysis of Multipolytype SiC Device Configurations

1994 ◽  
Vol 375 ◽  
Author(s):  
W. Huang ◽  
S. Wang ◽  
M. Dudley ◽  
P. Neudeck ◽  
J. A. Powell ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Structure Defect ◽  
Defect Structures ◽  
Topographic Analysis ◽  
X Ray ◽  
Back Reflection ◽  
White Beam ◽  
Computer Aided

AbstractSiC device configurations comprising various polytypes have been analyzed using synchrotron white beam x-ray topography with the aid of computer simulation. Diffracted intensity maps for the various polytypes and their combinations in various diffraction geometries, including transmission, reflection, grazing-reflection and back-reflection are generated. This method is used to determine the structures of SiC devices fabricated via CVD epilayer growth of nominally 3C-SiC or 6H-SiC, or 6H-SiC substrates grown by the Lely technique. The work indicates that those devices which were initially considered to be of 3C structure also contain some 6H structure. Defect structures associated with the polytype configurations are also presented.

X-Ray Topographic Studies of Defects in PVT 6H-SiC Substrates and Epitaxial 6H-SiC Thin Films

1994 ◽  
Vol 339 ◽  
Author(s):  
S. Wang ◽  
M. Dudley ◽  
C. H. Carter ◽  
H. S. Kong
Keyword(s):  
Thin Films ◽  
Basal Plane ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Epitaxial Thin Films ◽  
Defect Structures ◽  
Screw Dislocations ◽  
X Ray ◽  
Back Reflection ◽  
White Beam

ABSTRACTSynchrotron white beam X-ray topography has been used to characterize defect structures in (0001) 6H-SiC substrates grown by the sublimation physical vapor transport (PVT) technique as well as in 6H-SiC epitaxial thin films grown on these substrates. Defects revealed in 6H-SiC substrates include super screw dislocations and basal plane dislocations. It has been found that back-reflection topographs are particularly suitable for imaging such super screw dislocations as well as basal plane dislocations whenever transmission topography is not applicable. Epitaxial 6H-SiC thin films grown on such (0001) substrates (tilted a few degrees towards the a-axis) were also examined by using surface sensitive grazing Bragg-Laue topography. It has been shown that super screw dislocations were replicated in the epitaxial thin films but no basal plane dislocations were revealed in the thin films. Results from various topographic techniques are discussed.

Characterization of Defect Structures in 3C-SiC Single Crystals Using Synchrotron White Beam X-ray Topography

1996 ◽  
Vol 423 ◽  
Author(s):  
W. Huang ◽  
M. Dudley ◽  
C. Fazi
Keyword(s):  
Single Crystals ◽  
Stacking Faults ◽  
Interference Microscopy ◽  
Defect Structures ◽  
Growth Sector ◽  
X Ray ◽  
Partial Dislocations ◽  
White Beam ◽  
Transmission And Reflection

AbstractDefect structures in (111) 3C-SiC single crystals, grown using the Baikov technique, have been studied using Synchrotron White Beam X-ray Topography (SWBXT). The major types of defects include complex growth sector boundary structures, double positioning twins, stacking faults on { 111 } planes, inclusions and dislocations (including growth dislocations and partial dislocations bounding stacking faults). Detailed stacking fault and double positioning twin configurations are determined using a combination of Nomarski interference microscopy, SEM and white beam x-ray topography in both transmission and reflection geometries. Possible defect generation phenomena are discussed.

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.

Orientation of Back Reflection Laue Photographs: A Semi-Automated Approach

1975 ◽  
Vol 19 ◽  
pp. 725-734 ◽  
Author(s):  
R. P. Goehner
Keyword(s):  
Computer Simulation ◽  
Single Crystals ◽  
Stereographic Projection ◽  
Crystallographic Plane ◽  
Polycrystalline Materials ◽  
Laue Pattern ◽  
X Ray ◽  
Lattice Constants ◽  
Stereographic Triangle ◽  
Back Reflection

Computer simulation of back reflection Laue patterns now provides the means to plot Laue patterns for any crystal system in any orientation. This capability makes it possible to determine, rapidly and accurately, the orientation of single crystals and large grains in polycrystalline materials even in cases where little or no symmetry is displayed in the Laue photograph. A set of standard Laue patterns is first simulated to cover the stereographic triangle of the crystal being studied. The Laue photograph obtained from the crystal, or grain, is compared with the set of simulated Laue patterns. The pattern most similar to the photograph is used to determine the (HKL) values of three Laue spots. The (HKL) values of these spots and half their angular separations from the x-ray beam, along with the lattice constants, are used by a computer program to calculate the (HKL) value of the crystallographic plane perpendicular to the x-ray beam. A simulated Laue pattern can now be obtained in exactly the same orientation and it can be drawn directly to the scale of the Laue photograph. Thus the validity of the orientation can be easily verified by direct comparison. The (HKL) value of the crystallographic plane perpendicular to the x-ray beam can also be used to plot a stereographic projection of the crystal poles. Therefore, the complete orientation of the crystal can be determined.

Characterization of Defect Structures in Lely 6H-SiC Single Crystals Using Synchrotron White Beam X-Ray Topography

1994 ◽  
Vol 375 ◽  
Author(s):  
W. Huang ◽  
S. Wang ◽  
M. Dudley ◽  
P. Neudeck ◽  
J. A. Powell ◽  
...  
Keyword(s):  
Single Crystals ◽  
Basal Plane ◽  
Stacking Faults ◽  
Defect Structures ◽  
Dislocation Generation ◽  
X Ray ◽  
Partial Dislocations ◽  
White Beam ◽  
Generation Mechanisms

AbstractDefect structures in Lely SiC single crystals have been studied using synchrotron white beam X-ray topography. Basal plane dislocations and stacking faults probably generated during post-growth cooling are clearly revealed. For both perfect dislocations and partial dislocations bounding the stacking faults, Burgers vectors and line directions are determined from contrast extinction analysis as well as projected direction analysis on different topographic images. The fault planes and fault vectors of the stacking faults were determined using contrast extinction analysis. Possible dislocation generation mechanisms are briefly discussed.

The contrast of inclusions compared with that of micropipes in back-reflection synchrotron white-beam topographs of SiC

2004 ◽  
Vol 37 (2) ◽  
pp. 200-203 ◽  
Author(s):  
W. M. Vetter ◽  
M. Dudley
Keyword(s):  
Screw Dislocation ◽  
Spherical Inclusion ◽  
Vertical Displacement ◽  
Displacement Function ◽  
Elastic Displacement ◽  
X Ray ◽  
Back Reflection ◽  
White Beam ◽  
Light Contrast ◽  
Section Topographs

Images of inclusions in synchrotron white-beam back-reflection X-ray topographs appear as spots of light contrast surrounded by darker rings, resembling images of micropipes, which appear as distinct white circles surrounded by dark rings. Section topographs taken across the centers of micropipes gave vertically displaced two-tailed images, arising from the helical tilt of the reflecting planes about the micropipes' screw dislocation axes. Section topographs taken across the inclusions showed no vertical displacement, only dark bars bracketing a region of depleted contrast, arising from the convex bulge of the reflecting planes lying above the inclusion. The features of the inclusion images could be reproduced in computer simulations based on the elastic displacement function of a spherical inclusion in a semi-infinite solid, and compared with others based on the displacement function of a screw dislocation in an infinite solid.

Harmonic composition of synchrotron white-beam X-ray topographic back-reflection images of basal-cut silicon carbide single-crystal wafers

1998 ◽  
Vol 31 (5) ◽  
pp. 820-822 ◽  
Author(s):  
W. M. Vetter ◽  
M. Dudley
Keyword(s):  
Silicon Carbide ◽  
Single Crystal ◽  
Higher Harmonics ◽  
X Ray ◽  
Black Rings ◽  
Back Reflection ◽  
White Beam ◽  
Harmonic Composition ◽  
Penetration Depths ◽  
Striking Contrast

Superscrew dislocations are visible in back-reflection synchrotron white-beam X-ray topographs of basal-cut SiC wafers in striking contrast as black rings surrounding white circles, even though such topographs suffer from extensive harmonic contamination. The contributions to the synchrotron white-beam topograph of each member of its series of harmonic reflections, {\bf g}=(0006n), where n=3 to 16, were calculated. Through intensity considerations and comparison with a {\bf g}=00018 topograph taken with Cu Kα1radiation, the {\bf g}=00024 harmonic was determined to be the most important contributor. The contrast of features lying deep beneath the crystal's surface was attributed to higher harmonics with larger penetration depths.

Mapping of Defects in Large-Area Silicon Carbide Wafers via Photoluminescence and its Correlation with Synchrotron White Beam X-Ray Topography

2008 ◽  
Vol 600-603 ◽  
pp. 549-552 ◽  
Author(s):  
Yi Chen ◽  
R. Balaji ◽  
Michael Dudley ◽  
Madhu Murthy ◽  
Serguei I. Maximenko ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Grain Boundaries ◽  
Comparative Studies ◽  
Large Scale ◽  
Grazing Incidence ◽  
Defect Structures ◽  
Large Area ◽  
X Ray ◽  
White Beam ◽  
Defect Microstructure

Comparative studies of defect microstructure in 4H-SiC wafers have been carried out using photoluminescence (PL) imaging and grazing-incidence Synchrotron White Beam X-ray Topography. Images of low angle grain boundaries on the PL images correlate well with SWBXT observations, and similar correlation can be established for some micropipe images although the latter is complicated by the overall level of distortion and misorientation associated with the low angle grain boundaries and the fact that many of the micropipes are located in or close to the boundaries. This validation indicates that PL imaging may provide a rapid way of imaging such defect structures in large-scale SiC wafers.

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