Sense determination of micropipes via grazing-incidence synchrotron white beam x-ray topography in 4H silicon carbide

Chen, Y.; Dhanaraj, Govindhan; Dudley, Michael; Sanchez, Edward; MacMillan, M. F.

doi:10.1063/1.2772190

Cited by 22 publications

(15 citation statements)

References 11 publications

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“…This is characteristic of threading screw dislocations and the slant direction has previously been utilized to determine handednesses of screw dislocations in SiC. 29,30 C. Defect selective etching Defect selective etching was performed to investigate whether SR-XRT images corresponding to dislocations with a Burgers vector a multiple of c truly are single dislocations or groups of dislocations in close proximity. Before comparing DSE and SR-XRT images, the sizes and appearances of the different types of threading dislocations in DSE images needed to be determined.…”

Section: B Threading Mixed Dislocationsmentioning

confidence: 99%

Synchrotron radiation x-ray topography and defect selective etching analysis of threading dislocations in GaN

Sintonen

Rudziński

Suihkonen

et al. 2014

Journal of Applied Physics

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The crystal quality of bulk GaN crystals is continuously improving due to advances in GaN growth techniques. Defect characterization of the GaN substrates by conventional methods is impeded by the very low dislocation density and a large scale defect analysis method is needed. White beam synchrotron radiation x-ray topography (SR-XRT) is a rapid and non-destructive technique for dislocation analysis on a large scale. In this study, the defect structure of an ammonothermal c-plane GaN substrate was recorded using SR-XRT and the image contrast caused by the dislocation induced microstrain was simulated. The simulations and experimental observations agree excellently and the SR-XRT image contrasts of mixed and screw dislocations were determined. Apart from a few exceptions, defect selective etching measurements were shown to correspond one to one with the SR-XRT results

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Section: B Threading Mixed Dislocationsmentioning

confidence: 99%

Synchrotron radiation x-ray topography and defect selective etching analysis of threading dislocations in GaN

Sintonen

Rudziński

Suihkonen

et al. 2014

Journal of Applied Physics

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“…16 Chen et al also employed this orientation contrast mechanism to successfully interpret TSD/MP images in a grazing-incidence geometry, enabling determination of their dislocation sense. 9,10 These studies indicate that orientation contrast rather than extinction contrast is the dominant determinant of the contrast of TSDs on reflection topographs. Furthermore, Huang et al recently explained the contrast variation of BPDs observed in SiC back-reflection topographs based on this orientation contrast mechanism.…”

Section: Resultsmentioning

confidence: 95%

“…On the other hand, synchrotron X-ray topography has been a powerful tool for defect analysis, and the complete characters of defects, such as their line direction, Burgers vector, and even dislocation sense, can be obtained. 9,10 Recently Huang has reported two types of basal plane dislocation (BPD) images observed in back-reflection Xray topography and found that the contrast variation is attributable to the defocusing/focusing of the diffracted X-rays due to the edge component of the BPD, which creates a convex/concave distortion of the basal planes. 11 This enables the precise description of the BPDs such as the glide direction under a certain shear stress.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Electron–Hole Recombination-Activated Partial Dislocations and Their Behavior in 4H-SiC Epitaxial Layers

Chen

Zhang

Dudley

et al. 2007

Journal of Elec Materi

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Electron-hole recombination-activated partial dislocations in 4H silicon carbide homoepitaxial layers and their behavior have been studied using synchrotron X-ray topography and electroluminescence. Stacking faults whose expansion was activated by electron-hole recombination enhanced dislocation glide were observed to be bounded by partial dislocations, which appear as white stripes or narrow dark lines in back-reflection X-ray topographs recorded using the basal plane reflections. Such contrast variations are attributable to the defocusing/focusing of the diffracted X-rays due to the edge component of the partial dislocations, which creates a convex/concave distortion of the basal planes. Simulation results based on the ray-tracing principle confirm our argument. Observations also indicate that, when an advancing partial dislocation interacts with a threading screw dislocation, a partial dislocation dipole is dragged behind in its wake. This partial dislocation dipole is able to advance regardless of the immobility of the C-core segment. A kink pushing mechanism is introduced to interpret the advancement of this partial dislocation dipole.

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“…Numerous MPs have been examined by comparing the grazing-incidence topograph and their corresponding reticulographic images and full agreement has been obtained. 16 By way of further verification, transmission crosssectional SWBXT has been carried out on crosssectional samples containing MPs. It has been established that transmission SWBXT of crosssectional samples can be used to unambiguously determine the sense of MPs in SiC.…”

Section: Resultsmentioning

confidence: 99%

Simulation of Grazing-Incidence Synchrotron White Beam X-ray Topographic Images of Micropipes in 4H-SiC and Determination of Their Dislocation Senses

Chen

Dudley

Sanchez

et al. 2007

Journal of Elec Materi

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Detailed comparison has been drawn between synchrotron white beam X-ray topographic images of micropipes in 4H-SiC, recorded using pyramidal plane reflections in grazing-incidence geometry, and images simulated using the ray-tracing method. The simulations were carried out with and without the influence of surface relaxation effects. The images simulated in the absence of surface relaxation effects appear as white elliptical shaped features, canted to one side or other of the g-vector (depending on the dislocation sense), surrounded by a dark contrast perimeter which thickens at both ends of the major axis and which exhibits two fold symmetry axes parallel to the major and minor axes. On the other hand, on the images simulated taking into account the effects of surface relaxation, the features are again canted to one side or other of the g-vector (depending on the dislocation sense) but do not exhibit the same symmetry in that one of the sides of the oval shape is flattened (along the major axis) and the distribution of intensity around the perimeter no longer possesses the two fold symmetry axes parallel to the major and minor axes. While the details of the distribution of the dark perimeter contrast observed on the recorded images are not so easy to correlate with the simulated distributions, the sense of cant of the roughly elliptical white features on the observed images can be easily correlated with the simulations. Since the sense of cant has the same behavior as a function of dislocation sense for simulations carried out with and without surface relaxation, this provides a high level of confidence that the sense of cant of these features can be readily used to determine the senses of the micropipes.

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Sense determination of micropipes via grazing-incidence synchrotron white beam x-ray topography in 4H silicon carbide

Cited by 22 publications

References 11 publications

Synchrotron radiation x-ray topography and defect selective etching analysis of threading dislocations in GaN

Synchrotron radiation x-ray topography and defect selective etching analysis of threading dislocations in GaN

Investigation of Electron–Hole Recombination-Activated Partial Dislocations and Their Behavior in 4H-SiC Epitaxial Layers

Simulation of Grazing-Incidence Synchrotron White Beam X-ray Topographic Images of Micropipes in 4H-SiC and Determination of Their Dislocation Senses

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