Analysis of Dislocation Contrast in Synchrotron Grazing-incidence X-ray Topographs and Ray-tracing Simulation in Off-axis 4H-SiC Crystals

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.

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Analysis of Dislocations in PVT-Grown 6H-SiC through Grazing-Incidence X-Ray Topographic Images and Ray-Tracing Simulation

ECS Transactions ◽

10.1149/09806.0133ecst ◽

2020 ◽

Vol 98 (6) ◽

pp. 133-145

Author(s):

Qianyu Cheng ◽

Tuerxun Ailihumaer ◽

Hongyu Peng ◽

Yafei Liu ◽

Balaji Raghothamachar ◽

...

Keyword(s):

Ray Tracing ◽

Grazing Incidence ◽

X Ray ◽

Ray Tracing Simulation

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Simulation of Grazing-Incidence Synchrotron X-ray Topographic Images of Threading c+a Dislocations in 4H-SiC

MRS Proceedings ◽

10.1557/opl.2012.1050 ◽

2012 ◽

Vol 1433 ◽

Cited By ~ 12

Author(s):

Fangzhen Wu ◽

Shayan Byrappa ◽

Huanhuan Wang ◽

Yi Chen ◽

Balaji Raghothamachar ◽

...

Keyword(s):

Ray Tracing ◽

Potassium Hydroxide ◽

Grazing Incidence ◽

Burgers Vector ◽

X Ray ◽

Edge Dislocations ◽

Ray Tracing Simulation ◽

Simulated Images ◽

Non Destructive ◽

Vector Magnitude

ABSTRACTSynchrotron X-ray topography (SXRT) of various geometries has been successfully utilized to image c+a dislocations in 4H-SiC crystals. Although molten potassium hydroxide(KOH) can be used to reveal the location of such dislocations, it is not possible to determine their senses or their Burgers vector magnitude. A simple, non-destructive method has been proposed to determine the Burgers vector of these c+a dislocations called the ray tracing simulation, which has been successfully implemented previously in revealing the dislocation sense and magnitude of micropipes, closed-core threading screw dislocations (TSDs) and threading edge dislocations (TEDs) in 4H-SiC. In this paper, grazing incidence topography is performed using the monochromatic beam for the horizontally cut wafers to record pyramidal reflections of 11-28 type. Ray tracing simulation has been successfully implemented to correlate the simulated images with experimental images which are discussed in the paper.

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Analysis of Dislocation Contrast in Synchrotron Grazing-incidence X-ray Topographs and Ray-tracing Simulation in Off-axis 4H-SiC Crystals

ECS Meeting Abstracts ◽

10.1149/ma2021-02341007mtgabs ◽

2021 ◽

Vol MA2021-02 (34) ◽

pp. 1007-1007

Author(s):

Tuerxun Ailihumaer ◽

Hongyu Peng ◽

Yafei Liu ◽

Qianyu Cheng ◽

Zeyu Chen ◽

...

Keyword(s):

Ray Tracing ◽

Grazing Incidence ◽

X Ray ◽

Ray Tracing Simulation

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Analysis of Dislocations in PVT-Grown 6H-SiC through Grazing-Incidence X-Ray Topographic Images and Ray-Tracing Simulation

ECS Meeting Abstracts ◽

10.1149/ma2020-02261842mtgabs ◽

2020 ◽

Vol MA2020-02 (26) ◽

pp. 1842-1842

Author(s):

Qianyu Cheng ◽

Tuerxun Ailihumaer ◽

Hongyu Peng ◽

Yafei Liu ◽

Balaji Raghothamachar ◽

...

Keyword(s):

Ray Tracing ◽

Grazing Incidence ◽

X Ray ◽

Ray Tracing Simulation

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Influence of surface relaxation on the contrast of threading edge dislocations in synchrotron X-ray topographs under the condition of g · b = 0 and g · b × l = 0

Journal of Applied Crystallography ◽

10.1107/s160057672100025x ◽

2021 ◽

Vol 54 (2) ◽

Author(s):

Hongyu Peng ◽

Tuerxun Ailihumaer ◽

Fumihiro Fujie ◽

Zeyu Chen ◽

Balaji Raghothamachar ◽

...

Keyword(s):

Ray Tracing ◽

Depth Profiling ◽

Simulation Method ◽

Surface Relaxation ◽

X Ray ◽

Relaxation Effects ◽

Orientation Contrast ◽

Relaxation Depth ◽

Edge Dislocations ◽

Ray Tracing Simulation

Residual contrast of threading edge dislocations is observed in synchrotron back-reflection X-ray topographs of 4H-SiC epitaxial wafers recorded using basal plane reflections where both g · b = 0 and g · b × l = 0. The ray-tracing simulation method based on the orientation contrast formation mechanism is applied to simulate images of such dislocations by applying surface relaxation effects. The simulated contrast features match the observed features on X-ray topographs, clearly demonstrating that the contrast is dominated by surface relaxation. Depth profiling indicates that the surface relaxation primarily takes place within a depth of 5 µm below the surface.

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Dislocation contrast on X-ray topographs under weak diffraction conditions

Journal of Applied Crystallography ◽

10.1107/s1600576721006592 ◽

2021 ◽

Vol 54 (4) ◽

Author(s):

Hongyu Peng ◽

Tuerxun Ailihumaer ◽

Yafei Liu ◽

Balaji Raghotharmachar ◽

Xianrong Huang ◽

...

Keyword(s):

Ray Tracing ◽

Grazing Incidence ◽

Local Lattice Distortion ◽

Rocking Curve ◽

Distinctive Features ◽

X Ray ◽

Orientation Contrast ◽

Weak Beam ◽

Local Lattice ◽

Contrast Analysis

The contrast of dislocations in 4H-SiC crystals shows distinctive features on grazing-incidence X-ray topographs for diffraction at different positions on the operative rocking curve. Ray-tracing simulations have previously been successfully applied to describe the dislocation contrast at the peak of a rocking curve.The present work shows that the dislocation images observed under weak diffraction conditions can also be simulated using the ray-tracing method. These simulations indicate that the contrast of the dislocations is dominated by orientation contrast. Analysis of the effective misorientation reveals that the dislocation contrast in weak-beam topography is more sensitive to the local lattice distortion, consequently enabling information to be obtained on the dislocation sense which cannot be obtained from the peak.

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