Formation Mechanism of Stacking Faults in PVT 4H-SiC Created by Deflection of Threading Dislocations with Burgers Vector c+a

Dudley, Michael; Wang, Huan Huan; Wu, Fangzhen; Byrapa, Sha Yan; Raghothamachar, Balaji; Choi, Gloria; Sanchez, Edward; Hansen, David M.; Drachev, Roman; Mueller, Stephan G.; Loboda, Mark J.

doi:10.4028/www.scientific.net/msf.679-680.269

Cited by 30 publications

(19 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sato et al showed that macrosteps with heights of 100-1800 nm also led to the transformation of TSDs into Frank type stacking faults during the PVT growth of SiC [11] . The formation of stacking faults by the deflection of dislocations in the PVT growth was also shown by Dudley et al in [12]. It is conceivable that the macrosteps formed on the growth interface of crystal B led to the transformation of several threading dislocations into defects in the basal plane, leaving the crystal at the crystal flanks.…”

Section: Discussionmentioning

confidence: 55%

Influence of the growth interface shape on the defect characteristics in the facet region of 4H-SiC single crystals

Arzig

Salamon

Hsiao

et al. 2020

Journal of Crystal Growth

View full text Add to dashboard Cite

Two 75mm 4H-SiC single crystals are grown by the physical vapor transport (PVT) technique, using different insulation materials. The insulation material of higher thermal conductivity led to an increased radial temperature gradient. The evolution of the growth front was monitored using the in-situ computed tomography (CT). A slightly bent growth interface and a bigger facet are formed during the growth applying a lower radial temperature gradient while a smaller facet and steeper crystal flanks are formed in the case of the larger radial temperature gradient. Micropipes are deflected laterally by large surface steps on the steep crystal flanks and a reduction of threading edge dislocations by 60% is revealed by KOH defect etching.

show abstract

Section: Discussionmentioning

confidence: 55%

Influence of the growth interface shape on the defect characteristics in the facet region of 4H-SiC single crystals

Arzig

Salamon

Hsiao

et al. 2020

Journal of Crystal Growth

View full text Add to dashboard Cite

show abstract

“…The original PVT growth is carried out on the C-face of the seed crystal. As has been described previously, threading dislocations with c-component of Burgers vectors are prone to being deflected onto the basal plane close to the outer edges of the growing boules due to overgrowth by macrosteps which are prevalent in these regions due to the curvature of the growth interface [5][6]. This is shown most clearly on transmission topographs recorded from axial slices cut parallel to the growth direction of the boule as shown in Figs.…”

Section: Resultsmentioning

confidence: 85%

Stacking Fault Formation during Homo-Epitaxy of 4H-SiC

Wang

Yang

et al. 2014

ECS Trans.

Self Cite

View full text Add to dashboard Cite

Synchrotron topographic and optical microscopic studies are presented of stacking faults formed during homo-epitaxy of 4H-SiC. Grazing incidence synchrotron white beam x-ray topographs reveal V and Y shaped features which transmission topographs reveal to be ¼[0001] Frank-type stacking faults. Geometric analysis of the size and shape of these faults indicates that they are fully contained within the epilayer and appear to be nucleated at the substrate/epilayer interface. Detailed analysis shows that the positions of the V shape stacking faults match with the positions of c-axis threading dislocations with Burgers vectors of c or c+a in the substrate and thus appear to result from the deflection of these dislocations during epilayer growth. Similarly, the Y shaped defects match well with the substrate surface intersections of c-axis threading dislocations with Burgers vectors of c or c+a in the substrate which were deflected onto the basal plane during substrate growth. A model for their formation mechanism is presented. IntroductionIt is generally acknowledged that defects within the active regions of 4H-SiC devices can have a deleterious effect on their performance. Since most of the defects in homoepitaxial layers are inherited from the substrate, much effort has recently been expended on minimizing the substrate defect densities. However, for the finite density of defects that currently remains in the substrate, a key issue is understanding how they propagate into the epilayer since this can present an opportunity to engineer the defect configuration in the epilayer. For example, if basal plane dislocations (BPDs) are allowed to propagate into the epilayer and result in the formation of Shockley stacking faults they are known to cause forward voltage drop in pin devices [1]. Consequently, much effort has been devoted to ensuring that basal plane dislocations are converted to relatively benign threading edge dislocations (TEDs) at the substrate-epilayer interface. This is achieved through modification of surface morphology (etching) [2] or by the use of epilayer growth interruptions [3]. Generally speaking, all defects piercing the substrate growth surface must propagate into the epilayer either in their original form or alternatively be deflected into a different direction of propagation. In all cases, the displacement vectors associated with the defects must be conserved across the interface. In this paper we present observations of epilayer defects predominantly observed close to the edges of an n-buffer plus n-type drift structure. These defects appear to be faint needle-like linear surface morphological features. Synchrotron white beam topography images show that 10.1149/06407.0125ecst ©The Electrochemical Society ECS Transactions, 64 (7) 125-131 (2014) 125 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.218.248.200 Downloaded on 2015-04-10 to IP

show abstract

“…Stacking faults in the substrates have gained some attention recently and in our previous work four kinds of stacking faults have been reported in terms of their fault vectors, e.g. Shockley faults, Frank faults, Shockley plus c/2 Frank faults, and Shockley plus c/4 Frank faults [1][2][3]. Generally speaking, defects reaching the growth surface will extend into the epi layer and may potentially harm the performance of devices grown on it.…”

Section: Introductionmentioning

confidence: 98%

“…

…”

mentioning

confidence: 99%

Direct Observation of Stacking Fault Nucleation from Deflected Threading Dislocations with Burgers Vector c+a in PVT Grown 4H-SiC

Wang

Raghothamachar

et al. 2014

MRS Proc.

Self Cite

View full text Add to dashboard Cite

In our previous studies [1][2][3], four kinds of stacking faults in 4H-SiC bulk crystal have been distinguished based on their contrast behavior differences in synchrotron white beam x-ray topography images. These faults are Shockley faults, Frank faults, Shockley plus c/2 Frank faults, and Shockley plus c/4 Frank faults. Our proposed formation mechanisms for these stacking faults involve the overgrowth of the surface outcrop associated with threading screw dislocations (TSDs) or threading mixed dislocations (TMDs) with Burgers vector of c+a by macrosteps and the consequent deflection of TSDs or TMDs onto the basal plane. Previous synchrotron x-ray topography observations were made in offcut basal wafers using transmission geometry. In this paper, further evidence is reported to confirm the proposed stacking fault formation mechanism. Observations are made in axially cut slices with surface plane {11-20}. Several kinds of stacking faults are recognized and their contrast behavior agrees with the four kinds previously reported. Direct observation is obtained of a Shockley plus c/4 Frank stacking fault nucleating from a TMD deflected onto the basal plane. The contrast from stacking faults on the basal plane in the axial slices is enhanced by recording images after rotating the crystal about the active -1010 reflection vector enabling a broader projection of the basal plane.

show abstract

Formation Mechanism of Stacking Faults in PVT 4H-SiC Created by Deflection of Threading Dislocations with Burgers Vector c+a

Cited by 30 publications

References 14 publications

Influence of the growth interface shape on the defect characteristics in the facet region of 4H-SiC single crystals

Influence of the growth interface shape on the defect characteristics in the facet region of 4H-SiC single crystals

Stacking Fault Formation during Homo-Epitaxy of 4H-SiC

Direct Observation of Stacking Fault Nucleation from Deflected Threading Dislocations with Burgers Vector c+a in PVT Grown 4H-SiC

Contact Info

Product

Resources

About