X-Ray Three-Dimensional Topography Imaging of Basal-Plane and Threading-Edge Dislocations in 4H-SiC

2012 ◽  
Vol 717-720 ◽  
pp. 323-326 ◽  
Author(s):  
Ryohei Tanuma ◽  
Daisuke Mori ◽  
Isaho Kamata ◽  
Hidekazu Tsuchida
Keyword(s):  
Basal Plane ◽  
Three Dimensional ◽  
Strain Analysis ◽  
X Ray ◽  
Substrate Interface ◽  
3D Topography ◽  
Interface Strain ◽  
Edge Dislocations ◽  
First Time

This paper demonstrates the X-ray three-dimensional (3D) topography of basal-plane dislocations (BPDs) and threading edge dislocations (TEDs) in 4H-SiC for the first time. Stereographic topographs are obtained for BPDs and TEDs, showing the propagation of BPDs from a substrate to an epilayer and the conversion of BPDs into TEDs near the epilayer/substrate interface. Strain analysis is also demonstrated for a TED, providing the image of strains in the order of ±10-5. It is verified that the 3D topography is successfully applicable to BPDs and TEDs.

Imaging and Strain Analysis of Threading-Edge and Basal-Plane Dislocations in 4H-SiC Using X-Ray Three-Dimensional Topography

2012 ◽  
Vol 725 ◽  
pp. 3-6 ◽  
Author(s):  
Ryohei Tanuma ◽  
Daisuke Mori ◽  
Isaho Kamata ◽  
Hidekazu Tsuchida
Keyword(s):  
Basal Plane ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Cross Sectional ◽  
X Ray ◽  
Substrate Interface ◽  
Cross Sectional Imaging ◽  
Simulation Results ◽  
Sectional Imaging ◽  
Edge Dislocations

This paper demonstrates the X-ray three-dimensional topography of basal-plane dislocations (BPDs) and threading edge dislocations (TEDs) in 4H-SiC. Cross-sectional imaging shows the propagation of BPDs from a substrate to an epilayer and the conversion of BPDs into TEDs near the epilayer/substrate interface. The strain analysis of TEDs exhibits the image of strains in the order of ±10-5. The observed strain images correlate well to simulation results.

Behavior of Basal Plane Dislocations and Low Angle Grain Boundary Formation in Hexagonal Silicon Carbide

2007 ◽  
Vol 556-557 ◽  
pp. 231-234 ◽  
Author(s):  
Yi Chen ◽  
Govindhan Dhanaraj ◽  
William M. Vetter ◽  
Rong Hui Ma ◽  
Michael Dudley
Keyword(s):  
Silicon Carbide ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Basal Plane ◽  
Opposite Sign ◽  
Three Dimensional ◽  
Cross Slip ◽  
X Ray ◽  
Tilt Boundaries ◽  
Edge Dislocations

The interactions between basal plane dislocations (BPDs) and threading screw and edge dislocations (TSDs and TEDs) in hexagonal SiC have been studied using synchrotron white beam x-ray topography (SWBXT). TSDs are shown to strongly interact with advancing basal plane dislocations (BPDs) while TEDs do not. A BPD can cut through an individual TED without the formation of jogs or kinks. The BPDs were observed to be pinned by TSDs creating trailing dislocation dipoles. If these dipoles are in screw orientation segments can cross-slip and annihilate also potentially leaving isolated trailing loops. The three-dimensional (3D) distribution of BPDs can lead to aggregation of opposite sign edge segments leading to the creation of low angle grain boundaries (LAGBs) characterized by pure basal plane tilt of magnitude determined by the net difference in densities of the opposite sign dislocations. Similar aggregation can also occur against pre-existing prismatic tilt boundaries made up of TED walls with the net difference in densities of the opposite sign dislocations contributing some basal plane tilt character to the LAGB.

Formation of Extended Defects in 4H-SiC Induced by Ion Implantation/Annealing

2009 ◽  
Vol 615-617 ◽  
pp. 477-480 ◽  
Author(s):  
Masahiro Nagano ◽  
Hidekazu Tsuchida ◽  
Takuma Suzuki ◽  
Tetsuo Hatakeyama ◽  
Junji Senzaki ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Basal Plane ◽  
Defect Formation ◽  
Stacking Faults ◽  
Annealing Process ◽  
Extended Defects ◽  
X Ray ◽  
Substrate Interface ◽  
Aluminum Ions ◽  
Activation Annealing

Defect formation during the ion implantation/annealing process in 4H-SiC epilayers is investigated by synchrotron reflection X-ray topography. The 4H-SiC epilayers are subjected to an activation annealing process after Aluminum ions being implanted in the epilayers. The formation modes of extended defects induced by the implantation/annealing process are classified into the migration of preexisting dislocations and the generation of new dislocations/stacking faults. The migration of preexisting basal plane dislocations (BPDs) takes place corresponding to the ion implantation interface or the epilayer/substrate interface. The generation of new dislocations/stacking faults is confirmed as the formation of Shockley faults near the surface of the epilayer and BPD half-loops in the epilayer.

Characterization and Reduction of Defects in 4H-SiC Substrate and Homo-Epitaxial Wafer

2020 ◽  
Vol 1004 ◽  
pp. 387-392 ◽  
Author(s):  
Long Yang ◽  
Li Xia Zhao ◽  
Hui Wang Wu ◽  
Yafei Liu ◽  
Tuerxun Ailihumaer ◽  
...  
Keyword(s):  
Basal Plane ◽  
Chemical Vapor ◽  
Vapor Transport ◽  
Etching Time ◽  
X Ray ◽  
Half Loop ◽  
Dislocation Behavior ◽  
Edge Dislocations ◽  
Defect Morphology ◽  
Koh Etching

4H-SiC substrates and homo-epitaxial layers were obtained using the traditional methods of physical vapor transport and chemical vapor deposition. Defect morphology has been studied using both Synchrotron White Beam X-ray Topography and Monochromatic Beam X-ray Topography. Molten KOH etching method was adopted to further investigate the dislocation behavior mechanisms. Deflected dislocations were observed at the periphery regions in both substrate and epitaxial wafers. 3C polytypes and half loop arrays were observed in the 4H-SiC epitaxial wafer. It is also found that the majority of basal plane dislocations are converted to threading edge dislocations in the epitaxial wafer samples. The proportion of BPD to TED conversion depends on the surface step morphology and growth mode in epitaxial growth which in turn depends on the C/Si ratio. By the optimization of etching time prior to epitaxy and C/Si ratio, high-quality epitaxial wafers with extremely low basal plane dislocations densities (＜0.1 cm-2) was obtained.

Characterization of 100 mm Diameter 4H-Silicon Carbide Crystals with Extremely Low Basal Plane Dislocation Density

2010 ◽  
Vol 645-648 ◽  
pp. 291-294 ◽  
Author(s):  
Michael Dudley ◽  
Ning Zhang ◽  
Yu Zhang ◽  
Balaji Raghothamachar ◽  
Sha Yan Byrapa ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Dislocation Density ◽  
Basal Plane ◽  
X Ray ◽  
Repetitive Process ◽  
Basal Plane Dislocation ◽  
And Behavior ◽  
New Generation ◽  
Edge Dislocations

Synchrotron White Beam X-ray Topography (SWBXT) studies are presented of basal plane dislocation (BPD) configurations and behavior in a new generation of 100mm diameter, 4H-SiC wafers with extremely low BPD densities (3-4 x 102 cm-2). The conversion of non-screw oriented, glissile BPDs into sessile threading edge dislocations (TEDs) is observed to provide pinning points for the operation of single ended Frank-Read sources. In some regions, once converted TEDs are observed to re-convert back into BPDs in a repetitive process which provides multiple BPD pinning points.

The Evolution Rule of Three-Dimensional Structures of Graphite During Oxidation

NANO ◽  
2015 ◽  
Vol 10 (01) ◽  
pp. 1550014 ◽  
Author(s):  
Peicao Wang ◽  
Hongjuan Sun ◽  
Tongjiang Peng
Keyword(s):  
Functional Groups ◽  
Basal Plane ◽  
Interplanar Spacing ◽  
Three Dimensional ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Evolution Rule ◽  
Rule Of Three ◽  
Ft Ir

The graphite oxidation samples with different degrees of oxidation were prepared from natural flake graphite via a modified Hummers method with controlled addition of KMnO 4. The evolution of oxygen-containing functional groups was analyzed by Fourier transform infrared spectrometry (FT-IR) and X-ray photoelectron spectroscopy (XPS). The evolution rule of three-dimensional (3D) graphite structures during oxidation has been verified via X-ray diffraction (XRD). Experimental results show that the evolution of the interplanar spacing of samples during oxidation can be approximately divided into four stages. When the dosage of KMnO 4 is 0.5 g per 1 g of graphite (g/g), a graphite intercalation compound (GIC) is formed through intercalating reactions, and a slight increase is observed in the values of d100 and d110, suggesting that the π–π interactions which decrease the length of carbon–carbon bonds were partially disrupted. Adding additional KMnO 4 initiates the second stage, in which GIC begins to oxidize. The insertion of oxygen-containing functional groups in the graphene basal plane leads to dramatic changes in the values of d100 and d110. The d100 is greatly reduced while d110 increases slightly. These trends are attributed to the fact that the basal plane is stretched during the oxidation process. Further addition of KMnO 4 in the third stage leads to relatively small increases in the values of d100 and d110. This result is consistent with the evolution rule of hydroxyl groups. In this research, the evolution rule of the value of d001 is also clearly demonstrated. When the concentration of KMnO 4 is not more than 3.0 g/g, the value of products d001 keeps gradually increasing, indicating that oxygen-containing groups continue to form bonds with carbons in the basal plane, and that additional water molecules are adsorbed between the layers of the samples. All the interplanar spacing values (d001, d100 and d110) are reduced significantly in the fourth stage, when the amount of KMnO 4 added up to 4.0 g/g. FT-IR and XPS analyses demonstrate that the decrease in the values of d100 and d110 is due to a reduction in the content of external hydroxyl groups. The change in d001 is attributed to the partial release of water molecules confined in the interlayer spaces between adjacent sheets are partly released.

scholarly journals Characterization of Screw Dislocations in a 4H-Silicon Carbide Diode Using X-Ray Microbeam Three-Dimensional Topography

2009 ◽  
Vol 615-617 ◽  
pp. 251-254 ◽  
Author(s):  
Ryohei Tanuma ◽  
Tae Tamori ◽  
Yoshiyuki Yonezawa ◽  
Hirotaka Yamaguchi ◽  
Hirofumi Matsuhata ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Strain Field ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Hollow Core ◽  
Screw Dislocations ◽  
X Ray ◽  
Microplasma Breakdown ◽  
Symmetry Break

This paper describes the study of non-hollow-core elementary screw dislocations (SDs) in silicon carbide (SiC) diodes using X-ray microbeam three-dimensional topography. Strain analysis shows that typical screw dislocations having a symmetric strain field tend to cause microplasma breakdown, whereas deformed SDs do not. The symmetry break in SDs will relax the focussing of strain and lessen the formation of defects, thereby leading to the desirable non-leak property.

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