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 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.

Structural Analysis of Dislocations in Highly Nitrogen-Doped 4H-SiC Substrates

2010 ◽  
Vol 645-648 ◽  
pp. 311-314 ◽  
Author(s):  
Masakazu Katsuno ◽  
Noboru Ohtani ◽  
Masashi Nakabayashi ◽  
Tatsuo Fujimoto ◽  
Hirokatsu Yashiro ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Basal Plane ◽  
Selective Etching ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
High Concentration ◽  
X Ray ◽  
Nitrogen Doped ◽  
Low Resistivity

Dislocations in highly nitrogen-doped (N > 1×1019 cm-3) low-resistivity ( < 10 mcm) 4H-SiC substrates were investigated by photoluminescence imaging, synchrotron X-ray topography, and defect selective etching using molten KOH. The behavior of dislocations is discussed particularly in terms of their glide motion in the presence of a high concentration of nitrogen. The results indicate that nitrogen impurities up to mid 1019 cm-3 concentration do not show any discernible influence on the glide behavior of basal plane dislocations (BPDs) in 4H-SiC crystals grown by physical vapor transport (PVT) method.

Low Defect Density Bulk AlN Substrates for High Performance Electronics and Optoelectronics

2012 ◽  
Vol 717-720 ◽  
pp. 1287-1290 ◽  
Author(s):  
Balaji Raghothamachar ◽  
Rafael Dalmau ◽  
Baxter Moody ◽  
H. Spalding Craft ◽  
Raoul Schlesser ◽  
...  
Keyword(s):  
Single Crystal ◽  
Basal Plane ◽  
High Performance ◽  
Defect Density ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Threading Dislocations ◽  
Crystalline Perfection ◽  
X Ray

Using the physical vapor transport (PVT) method, single crystal boules of AlN have been grown and wafers sliced from them have been characterized by synchrotron white beam X-ray topography (SWBXT) in conjunction with optical microscopy. X-ray topographs reveal that the wafers contain dislocations that are inhomogeneously distributed with densities varying from as low as 0 cm-2 to as high as 104 cm-2. Two types of dislocations have been identified: basal plane dislocations and threading dislocations, both having Burgers vectors of type 1/3<112-0> indicating that their origin is likely due to post-growth deformation. In some cases, the dislocations are arranged in low angle grain boundaries. However, large areas of the wafers are nearly dislocation-free and section X-ray topographs of these regions reveal the high crystalline perfection.

Studies of the Distribution of Elementary Threading Screw Dislocations in 4H Silicon Carbide Wafer

2008 ◽  
Vol 600-603 ◽  
pp. 301-304 ◽  
Author(s):  
Yi Chen ◽  
Ning Zhang ◽  
Xian Rong Huang ◽  
David R. Black ◽  
Michael Dudley
Keyword(s):  
Silicon Carbide ◽  
Grazing Incidence ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Screw Dislocations ◽  
X Ray ◽  
Pyramidal Plane

The density and sense distribution of elementary threading screw dislocations in a physical vapor transport grown 3-inch 4H silicon carbide wafer have been studied. The density of TSDs ranges between 1.6×103/cm2 and 7.1×103/cm2 and the lowest density is observed at positions approximately half radius off the wafer center. The dislocation sense of elementary threading screw dislocations can be readily revealed by the asymmetric contrast of their images in grazing-incidence x-ray topographs using pyramidal plane reflections. The circumferential and radial distributions of the sense of elementary threading screw dislocations have been studied and no clear trends are observed in either distribution.

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.

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.

High Quality AlN Single Crystal Substrates for AlGaN-Based Devices

2018 ◽  
Vol 924 ◽  
pp. 923-926 ◽  
Author(s):  
Rafael Dalmau ◽  
H. Spalding Craft ◽  
Jeffrey Britt ◽  
Elizabeth Paisley ◽  
Baxter Moody ◽  
...  
Keyword(s):  
Aluminum Nitride ◽  
Single Crystal ◽  
Basal Plane ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
High Magnification ◽  
High Quality ◽  
X Ray ◽  
Surface Finishes ◽  
Edge Dislocations

Aluminum nitride (AlN) single crystal boules were grown by physical vapor transport (PVT). Diameter expansion during boule growth, without the introduction of low angle grain boundaries (LAGB) around the boule periphery, was confirmed by crossed polarizer imaging, synchrotron white beam x-ray topography (SWBXT), and synchrotron monochromatic beam x-ray topography (SMBXT). The densities of basal plane dislocations (BPD) and threading edge dislocations (TED) averaged from high-magnification topographs of five regions of a high-quality substrate were 0 cm-2 and 992 cm-2, respectively. Substrates fabricated from AlN boules possessed excellent surface finishes suitable for epitaxy.

Investigation of Low Angle Grain Boundaries in Hexagonal Silicon Carbide

2006 ◽  
Vol 955 ◽  
Author(s):  
Yi Chen ◽  
Hui Chen ◽  
Ning Zhang ◽  
Michael Dudley ◽  
Ronghui Ma
Keyword(s):  
Silicon Carbide ◽  
Grain Boundaries ◽  
Basal Plane ◽  
Vapor Transport ◽  
Threading Dislocations ◽  
Prismatic Plane ◽  
Screw Dislocations ◽  
X Ray ◽  
Edge Dislocations ◽  
Dislocation Walls

ABSTRACTInteraction between basal plane dislocations and single or well-spaced threading dislocations is discussed based on synchrotron white beam X-ray topographic studies carried out on physical vapor transport grown hexagonal silicon carbide single crystals. The basal plane dislocations are able to cut through single or well-spaced threading edge dislocations even if the formation of kinks/jogs is energetically unfavorable while threading screw dislocations were mostly observed to act as effective pinning points. However, basal plane dislocations can sometimes cut through a threading screw dislocation, forming a superjog and which subsequently migrates on the prismatic plane via a cross-slip process. Threading edge dislocation walls act as obstacles for the glide of basal plane dislocations and the mechanism by which this occurs is discussed. The character of low angle grain boundaries and their dislocation content are discussed.

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