Exploration of Bulk and Epitaxy Defects in 4H-SiC Using Large Scale Optical Characterization

2017 ◽  
Vol 897 ◽  
pp. 226-229
Author(s):  
R.T. Leonard ◽  
M.J. Paisley ◽  
S. Bubel ◽  
J.J. Sumakeris ◽  
A.R. Powell ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Basal Plane ◽  
Large Scale ◽  
Optical Characterization ◽  
Defect Level ◽  
Screw Dislocations ◽  
Density Distributions ◽  
Dislocation Defect ◽  
Defect Levels ◽  
Crystal Wafer

In this work, aggregate epitaxial carrot distributions are observed at the crystal, wafer and dislocation defect levels, instead of individual extended carrot defect level. From combining large volumes of data, carrots are observed when both threading screw dislocations (TSD) and basal plane dislocations (BPD) densities are locally high as seen in full wafer maps. Dislocation density distributions in areas of carrot formation are shown, and suggest TSD limit the formation of carrots in regions containing BPD. These data also add support for mechanisms requiring the need for both dissociated BPD and TSD for carrot formation.

scholarly journals MODELING OF NANOINDENTATION AND MICROSTRUCTURAL DUCTILE BEHAVIOR IN METALLIC MATERIAL SYSTEMS

2004 ◽  
Vol 841 ◽  
Author(s):  
Jeong Beom Ma ◽  
W. Ashmawi ◽  
M. A. Zikry ◽  
D. Schall ◽  
D. W. Brenner
Keyword(s):  
Dislocation Density ◽  
Grain Boundary ◽  
Large Scale ◽  
Dynamic Models ◽  
Local Stress ◽  
Stress Fields ◽  
Metallic Material ◽  
Density Distributions ◽  
Ductile Behavior ◽  
The Continuum

ABSTRACTSpecialized large-scale computational finite-element and molecular dynamic models have been used to understand and predict how dislocation density emission and contact stress fields due to nanoindentation affect inelastic deformation evolution at scales that span the molecular to the continuum level in ductile crystalline systems. Dislocation density distributions and local stress fields have been obtained for different crystalline slip-system and grain-boundary orientations. The interrelated effects of grain-boundary interfaces and orientations, dislocation density evolution and crystalline structure on indentation inelastic regions have been investigated.

scholarly journals The magnetic helicity density patterns from non-axisymmetric solar dynamo

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Valery V. Pipin
Keyword(s):  
Magnetic Field ◽  
Differential Rotation ◽  
Conservation Law ◽  
Large Scale ◽  
Solar Dynamo ◽  
Magnetic Helicity ◽  
Dynamo Model ◽  
Density Distributions ◽  
Large Scale Magnetic Field ◽  
Helicity Conservation

We study the helicity density patterns which can result from the emerging bipolar regions. Using the relevant dynamo model and the magnetic helicity conservation law we find that the helicity density patterns around the bipolar regions depend on the configuration of the ambient large-scale magnetic field, and in general they show a quadrupole distribution. The position of this pattern relative to the equator can depend on the tilt of the bipolar region. We compute the time–latitude diagrams of the helicity density evolution. The longitudinally averaged effect of the bipolar regions shows two bands of sign for the density distributions in each hemisphere. Similar helicity density patterns are provided by the helicity density flux from the emerging bipolar regions subjected to surface differential rotation.

Electrical and optical characterization of defect levels caused in InGaAs by boron ion implantation

1993 ◽  
Vol 80-81 ◽  
pp. 632-635
Author(s):  
Shin'ichi Yamamura ◽  
Tadamasa Kimura ◽  
Shigemi Yugo ◽  
Riichiro Saito ◽  
Michio Murata ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Optical Characterization ◽  
Defect Levels

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.

Dislocations Propagation Study Trough High-Resolution 4H-SiC Substrate Mapping

2019 ◽  
Vol 963 ◽  
pp. 276-279 ◽  
Author(s):  
Ruggero Anzalone ◽  
Nicolò Piluso ◽  
Andrea Severino ◽  
Simona Lorenti ◽  
Giuseppe Arena ◽  
...  
Keyword(s):  
High Resolution ◽  
Epitaxial Layer ◽  
Basal Plane ◽  
Stacking Faults ◽  
Screw Dislocations ◽  
Density Maps ◽  
Dislocations Density ◽  
Koh Etching

In this work a deep investigation of the dislocation on 4H-SiC substrate has been shown. The dislocation intersecting the surface were enhanced by KOH etching at 500 deg. C. performed on whole 6 inches substrate. A comparison between basal plane dislocations and threading screw dislocations in the substrate with the defects in the epitaxial layer (mainly stacking faults and carrots) was performed. The comparison between shows a correlation between basal plane dislocations density and stacking faults density maps.

X-ray topographic dislocation contrast visible in reflections orthogonal to the Burgers vectors of axial screw dislocations in hexagonal silicon carbide

2001 ◽  
Vol 34 (1) ◽  
pp. 20-26 ◽  
Author(s):  
W. M. Vetter ◽  
M. Dudley
Keyword(s):  
Silicon Carbide ◽  
Electron Microscope ◽  
Basal Plane ◽  
High Density ◽  
Screw Dislocations ◽  
X Ray ◽  
Apparent Violation ◽  
Light Contrast

Contrast is associated with micropipes in X-ray topographs of SiC crystals obtained with prismatic reflections, representing an apparent violation of theg·b= 0 invisibility criterion. This is explained as a population of basal-plane dislocations with Burgers vectors of the setb= {\textstyle{1 \over 3}}〈11{\bar{2}}0〉 that occur in a high density within a few micrometers of the micropipes, below the resolution of X-ray topography. These basal-plane dislocations could be observed under an electron microscope. The presence of the surfaces of the micropipes influences the dislocation images in the topographs taken with prismatic reflections, often resulting in a band of light contrast along the axes of the micropipes.

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