Studies of c-Axis Threading Screw Dislocations in Hexagonal SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Yi Chen ◽  
Xianrong Huang ◽  
Ning Zhang ◽  
Govindhan Dhanaraj ◽  
Edward Sanchez ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Grazing Incidence ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
X Ray ◽  
Back Reflection ◽  
Partial Dislocations ◽  
Ray Tracing Simulation ◽  
Vector Magnitude

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.

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

2012 ◽  
Vol 1433 ◽  
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.

High-Resolution X-ray Topography of Dislocations in 4H-SiC Epilayers

2006 ◽  
Vol 911 ◽  
Author(s):  
Isaho Kamata ◽  
Hidekazu Tsuchida ◽  
William M Vetter ◽  
Michael Dudley
Keyword(s):  
Computer Simulation ◽  
High Resolution ◽  
Grazing Incidence ◽  
Crystal Defects ◽  
Recording Media ◽  
Simulated Image ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
X Ray ◽  
Simulated Images

AbstractSilicon carbide (SiC) substrates and epilayers contain many crystal defects, such as micropipes, screw dislocations, threading edge dislocations (TEDs), basal plane dislocations (BPDs) and stacking faults. To investigate these defects, synchrotron radiation topography is frequently carried out. When the monochromatic synchrotron X-ray topography is taken by the grazing-incidence reflection geometry using 11-28 reflection, screw dislocations, TEDs and BPDs are simultaneously seen and shown as different topographic images [1]. Many studies of dislocations were reported using 11-28 reflections in 4H-SiC [1,2]. Topographic images of the dislocations have been analyzed by the ray-tracing method of computer simulation [3]. However, experimental images of dislocations were not fully matched to the fine structure of simulation images, because of a lack of resolution in recording media: conventional films and nuclear emulsion plates [3]. This time, we report obtaining high-resolution topographic images using a new recording medium, and compare results between the experiment and the computer simulation. Synchrotron topography in 11-28 reflection was carried out at SPring8 applying holography films as high-resolution recording media. The TED images are distinguished as four types, which have ribbon-like features with different rotating angles, through the use of the films. The four different TED images agree well with the computer simulated images which have been reported by Vetter et.al. taking into account of the different Burgers vector directions [3]. By comparing the three topographic images taken at g=-12-18, 11-28 and 2-1-18, we confirmed experimentally that the four types of TED images originated from the difference of Burgers vector directions. We also investigated high-resolution topographic images of elementary screw dislocations, micropipes, and BPDs in 4H-SiC epilayers. The experimental image of screw dislocation fairly matched with simulated image. The fine features in the experimental topographic images of micropipes and BPDs are also compared with the simulated images in detail. [1] T. Ohno, H. Yamaguchi, S. Kuroda, K. Kojima, T. Suzuki, K. Arai: J. cryst. Growth. Vol. 260 (2004) 209. [2] H. Tsuchida, T. Miyanagi, I. Kamata, T. Nakamura, R. Ishii, K. Nakayama and Y.Sugawara: Jpn. J. Appl. Phys. Vol. 25, (2005), L806-808. [3] W. Vetter, H. Tsuchida, I. Kamata, M. Dudley: J. Appl. Cryst. Vol. 38, (2005), 442-447.

Determination of Burgers Vector of Screw Dislocations in 6H-SiC Single Crystals by Synchrotron White Beam X-Ray Topography

1996 ◽  
Vol 437 ◽  
Author(s):  
W. Si ◽  
M. Dudley ◽  
C. Carter ◽  
R. Glass ◽  
V. Tsvetkov
Keyword(s):  
Single Crystals ◽  
Dislocation Core ◽  
Line Defect ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
X Ray ◽  
White Beam ◽  
Lattice Planes ◽  
Vector Magnitude

AbstractIndividual screw dislocations along the [0001] axis in 6H-SiC single crystals have been characterized by means of Synchrotron White Beam X-ray Topography (SWBXT). The magnitude of the Burgers vector was determined from: (1) the diameter of circular diffraction-contrast images of dislocations in back-reflection topographs, (2) the width of bi-modal images associated with screw dislocations in transmission topographs, (3) the magnitude of the tilt of the lattice planes on both sides of dislocation core in projection topographs, and (4) also the magnitude of the tilt of the lattice planes in section topographs. All of the four methods showed reasonable consistency. The sense of the Burgers vector can also be deduced from the abovementioned tilt of the lattice planes. Results revealed that in 6H-SiC a variety of screw dislocations can be found with Burgers vector magnitude ranging from 1c to 7c (c is the lattice constant along [0001] axis). This work demonstrates that SWBXT can be used as a quantitative technique for detailed analyses of line defect configurations.

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

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

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

2021 ◽  
Vol 104 (7) ◽  
pp. 157-169
Author(s):  
Tuerxun Ailihumaer ◽  
Hongyu Peng ◽  
Yafei Liu ◽  
Qianyu Cheng ◽  
Zeyu Chen ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Grazing Incidence ◽  
X Ray ◽  
Ray Tracing Simulation

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

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

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

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

Investigation of Defect Formation in 4H-SiC(0001) and (000-1) Epitaxy

2008 ◽  
Vol 600-603 ◽  
pp. 267-272 ◽  
Author(s):  
Hidekazu Tsuchida ◽  
Isaho Kamata ◽  
Masahiro Nagano
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Formation ◽  
Grazing Incidence ◽  
Microscopic Structure ◽  
Threading Dislocation ◽  
Simultaneous Generation ◽  
Burgers Vector ◽  
X Ray ◽  
Transmission Electron

Defect formation in 4H-SiC(0001) and (000-1) epitaxy is investigated by grazing incidence synchrotron reflection X-ray topography and transmission electron microscopy. Frank-type faults, which are terminated by four Frank partials with a 1/4[0001] type Burgers vector with the same sign on four different basal planes, are confirmed to be formed by conversion of a 1c threading edge dislocation (TSD) in the substrate as well as simultaneous generation of a 1c TSD during epitaxy. The collation between the topography appearance and the microscopic structure and the variety of Frank faults are shown. Formation of carrot defects and threading dislocation clusters are also investigated.

scholarly journals Breakdown Degradation Associated With Elementary Screw Dislocations In 4H-SiC P+N Junction Rectifiers

1997 ◽  
Vol 483 ◽  
Author(s):  
P. G. Neudeck ◽  
W. Huang ◽  
M. Dudley
Keyword(s):  
Video Camera ◽  
Initial Study ◽  
Hollow Core ◽  
Power Devices ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
X Ray ◽  
Current Voltage ◽  
The Impact ◽  
Sic Wafer

AbstractIt is well-known that SiC wafer quality deficiencies are delaying the realization of outstandingly superior 4H-SiC power electronics. While efforts to date have centered on eradicating micropipes (i.e., hollow core super-screw dislocations with Burgers vector > 2c), 4H-SiC wafers and epilayers also contain elementary screw dislocations (i.e., Burgers vector = Ic with no hollow core) in densities on the order of thousands per cm2, nearly 100-fold micropipe densities. This paper describes an initial study into the impact of elementary screw dislocations on the reverse-bias current-voltage (I-V) characteristics of 4H-SiC p+n diodes. First, Synchrotron White Beam X-ray Topography (SWBXT) was employed to map the exact locations of elementary screw dislocations within small-area 4H-SiC p+n mesa diodes. Then the high-field reverse leakage and breakdown properties of these diodes were subsequently characterized on a probing station outfitted with a dark box and video camera. Most devices without screw dislocations exhibited excellent characteristics, with no detectable leakage current prior to breakdown, a sharp breakdown I-V knee, and no visible concentration of breakdown current. In contrast devices that contained at least one elementary screw dislocation exhibited a 5% to 35% reduction in breakdown voltage, a softer breakdown I-V knee, and visible microplasmas in which highly localized breakdown current was concentrated. The locations of observed breakdown microplasmas corresponded exactly to the locations of elementary screw dislocations identified by SWBXT mapping. While not as detrimental to SiC device performance as micropipes, the undesirable breakdown characteristics of elementary screw dislocations could nevertheless adversely affect the performance and reliability of 4H-SiC power devices.

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