Characterization and Formation Mechanism of Six Pointed Star-Type Stacking Faults in 4H-SiC

Wu, Fangzhen; Wang, Huanhuan; Byrappa, Shayan; Raghothamachar, Balaji; Dudley, Michael; Wu, Peng; Xu, Xueping; Zwieback, Ilya

doi:10.1007/s11664-012-2379-9

Cited by 4 publications

(4 citation statements)

References 16 publications

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“…In this study, we report the formation of double Shockley faults in high doping regions of PVT-grown 4H-SiC wafers following a post-growth high temperature heat treatment. Similar stacking fault configurations have been previously reported [2].…”

Section: Introductionsupporting

confidence: 89%

“…Each stacking fault appears as a rhombus shape showing characteristic Shockley fault contrast in both -1100 and -1101 topographs as predicted by g.R analysis (Fig. 1) [2] while the bounding partial dislocations have Burgers vectors along the long diagonal of the rhombus i.e. <1-100> directions as determined by g.b analysis of 11-20 type reflections.…”

Section: Resultsmentioning

confidence: 65%

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Synchrotron X-Ray Topography Analysis of Double Shockley Stacking Faults in 4H-SiC Wafers

Yang

Guo

Goue

et al. 2016

MSF

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Synchrotron white beam X-ray topography studies carried out on 4H-SiC wafers characterized by locally varying doping concentrations reveals the presence of overlapping Shockley stacking faults generated from residual surface scratches in regions of higher doping concentrations after the wafers have been subjected to heat treatment. The fault generation process is driven by the fact that in regions of higher doping concentrations, a faulted crystal containing double Shockley faults is more stable than perfect 4H–SiC crystal at the high temperatures (>1000 °C) that the wafers are subject to during heat treatment. We have developed a model for the formation mechanism of the rhombus shaped stacking faults, and experimentally verified it by characterizing the configuration of the bounding partials of the stacking faults on both surfaces. Using high resolution transmission electron microscopy, we have verified that the enclosed stacking fault is a double Shockley type.

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Section: Introductionsupporting

confidence: 89%

Section: Resultsmentioning

confidence: 65%

Synchrotron X-Ray Topography Analysis of Double Shockley Stacking Faults in 4H-SiC Wafers

Yang

Guo

Goue

et al. 2016

MSF

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“…In addition, the morphology obtained by SEM is shown in Figure 4c,d, which is consistent with that obtained by the laser confocal microscope. Wu et al [13,14] reported that they found a new stacking fault in 4H-SiC wafers through synchrotron white-beam x-ray topography. This fault has the shape of a six-pointed star, comprising faults with three different fault vectors of Shockley type.…”

Section: Morphology and Structure Of The Star-like Defectmentioning

confidence: 99%

Forward Voltage Drop Induced by an Abnormal Threading Dislocation Aggregation in 4H-SiC GTO Devices

Cui

Chen

et al. 2019

Materials

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An abnormal star-like defect was found on the failed SiC gate turn-off thyristor (GTO) devices after metal removal and KOH etching at 450 °C in this work. It is of extraordinary larger size of 210–580 µm, even much larger than the etch pit of a micropipe in 4H-SiC. In addition, the abnormal star-like defect, exhibiting the consistent orientation with the six-fold symmetry of silicon carbide, was found to consist of several penetrating dislocations with the help of a LEXT OLS4000 3D laser confocal microscope. These abnormal star-like etch pits can severely reduce the forward blocking characteristic of GTOs, while exerting insignificant influence on the forward current-voltage characteristics between anode and gate electrode of the 4H-SiC GTO devices. Interestingly, the relationship between forward voltage drop and dislocation density is affected by the abnormal star-like defect. A regular increase of forward voltage drop at 100 A/cm2 was observed with the increasing dislocation density, while this correlation disappears in the presence of an abnormal star-like defect.

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“…McKelvey (28), Wertheim and Pearson (29) investigated the influence of dislocations on the recombination lifetime in germanium (Ge) samples and revealed an inverse relationship between lifetime τ r and dislocation density ρ d for ρ d ≥10 4 cm -2 . M. J. Marinella and coworkers further reported that at density higher that 10 6 cm -2 , dislocations limit carrier recombination lifetime in 4H-SiC (30). In light of the potential influence of extended and morphological defects on lifetime, investigation of their formation mechanism as it pertains to the growth conditions of the single crystal and assessment of their influence on minority carrier lifetime becomes necessary.…”

Section: Lifetime Measurementsmentioning

confidence: 99%

(Invited) Study of Minority Carrier Lifetime Killer by Synchrotron X-Ray Topography

et al. 2016

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The lifetime maps for a 2” n-type 4H-SiC quarter wafer (sample 1) and a 4” diameter half wafer (sample 2) were recorded using microwave photoconductive decay (μPCD) measurements and correlated with the synchrotron X-ray topography (SXRT) map of structural defects. The lifetime map of sample 1 revealed a drastic reduction in carrier lifetime along the edges and inside one of its facets (facet 1), correlated with microcracks, BPD loops, overlapping triangular defects, high density of multi-layer Shockley stacking faults (SFs) and low angle grain boundaries (LAGBs). Similarly, sample 2 showed a reduced carrier lifetime along the edges corresponding to regions of high density of overlapping triangular defects, microcracks and BPD loops in the SXRT map. Shorter lifetime observed in the middle region of sample 2 correlated with networks of interfacial dislocations (IDs) and half loop arrays (HLAs) originating from 3C inclusions that were generated during epilayers growth. Further analysis of the SXRT maps revealed the SFs in facet 1 were double Shockley stacking faults (DSSFs) that have likely nucleated from scratches present on the substrate surface and LAGBs present in that region, which propagated during epilayer growth. We discuss the mitigated influence of numerous morphological defects observed on the surface of both epilayer samples.

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Characterization and Formation Mechanism of Six Pointed Star-Type Stacking Faults in 4H-SiC

Cited by 4 publications

References 16 publications

Synchrotron X-Ray Topography Analysis of Double Shockley Stacking Faults in 4H-SiC Wafers

Synchrotron X-Ray Topography Analysis of Double Shockley Stacking Faults in 4H-SiC Wafers

Forward Voltage Drop Induced by an Abnormal Threading Dislocation Aggregation in 4H-SiC GTO Devices

(Invited) Study of Minority Carrier Lifetime Killer by Synchrotron X-Ray Topography

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