Structural analysis of double-layer Shockley stacking faults formed in heavily-nitrogen-doped 4H-SiC during annealing

Tokuda, Yasutaka; Yamashita, Takako; Kamata, Isaho; Naijo, T.; Miyazawa, Tatsuo; Hayashi, Shohei; Hoshino, Norihiro; Kato, Tomohisa; Okumura, Hajime; Kimoto, Tsunenobu; Tsuchida, Hidekazu

doi:10.1063/1.4996098

Cited by 23 publications

(17 citation statements)

References 37 publications

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“…This means that the oblique side of 1SSF has a 30° C(g) PD at the G4 layer. 33 In the SXRT image, as shown in Fig. 3c, the corresponding line has a dark contrast on the oblique side of the 1SSF.…”

Section: Resultsmentioning

confidence: 93%

Origin and Generation Process of a Triangular Single Shockley Stacking Fault Expanding from the Surface Side in 4H-SiC PIN Diodes

Ota

Nishio

Okada

et al. 2021

J. Electron. Mater.

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A triangular single Shockley stacking fault (1SSF) in 4H-SiC, expanding from the surface to the substrate/epilayer interface, was investigated. The triangular 1SSF was observed during electroluminescence examination of PIN diodes that had line-andspace anodes with open windows. The threshold current density of the 1SSF expansion was comparatively intermediate, and differed from that of a 1SSF that expanded from a basal plane dislocation (BPD) that had penetrated from the substrate into the epilayer, and from that of a 1SSF that expanded from a BPD that had converted into threading edge dislocations (TEDs) at the substrate/epilayer interface. No BPDs or surface damage such as cracks were observed by photoluminescence imaging, synchrotron x-ray topography imaging, or scanning electron microscope imaging near the origin of the expansion region. High-resolution observation using cross-sectional transmission electron microscopy showed that a partial dislocation (PD) was present on the basal plane and two inclined TEDs were present on both sides of the PD. A g•b analysis showed that this dislocation had a Burgers vector of ± (1/3) [1120], and it was estimated to be a combination of a TED-BPD-TED structure with a short BPD before expansion. Therefore, the triangular 1SSF from the surface side can be explained to have expanded from this BPD. Furthermore, considering the possibility of the BPD-TED conversion at the epitaxial growth process, the TED-BPD-TED dislocation was speculated to have formed after epitaxial growth. The perfect control of the forward voltage degradation of 4H-SiC device is thought to be realized by focusing on this type of BPD.

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Section: Resultsmentioning

confidence: 93%

Origin and Generation Process of a Triangular Single Shockley Stacking Fault Expanding from the Surface Side in 4H-SiC PIN Diodes

Ota

Nishio

Okada

et al. 2021

J. Electron. Mater.

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“…The FIB sampling position This means that an extra half-plane exists in the lower part, and the PD at Point A has a C-core structure. 44) In contrast, at Point B in Fig. 5(c), the number of atoms in the upper and lower lines is found to be the same.…”

Section: Plan-view Tem Imaging and G • B Analysismentioning

confidence: 79%

Single Shockley stacking fault expansion from immobile basal plane dislocations in 4H-SiC

Nishio

Okada

Ota

et al. 2020

Jpn. J. Appl. Phys.

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Some combinations of immobile partial dislocations (PDs) that constitute basal plane dislocations (BPDs) have not previously been considered as sources for single Shockley stacking fault expansion. We searched for and found this type of BPD and investigated its structure. The realistic reason for immobile C-core PDs being converted into mobile Si-core PDs is speculated from the results obtained by plan-view transmission electron microscopy (TEM) and cross-sectional scanning TEM. A model is proposed from a dynamic viewpoint for interpreting the mechanism of core-species change by step-flow motion during epitaxial crystal growth in 4H-SiC. Moreover, all possible combinations of immobile PDs are summarized and the necessary condition for immobile BPDs to change to include mobile PDs is discussed.

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“…The wide band gap, high electric breakdown field, high electron mobility, and high thermal conductivity of 4H silicon carbide (4H-SiC) have positioned it as the leading candidate in high-power and high-frequency electronics. − Although 4H-SiC has been successfully used in the applications, such as electronic vehicles and power transmission systems, the high-density dislocations still pose severe degradation on the performance of 4H-SiC-based devices. − Threading screw dislocations (TSDs) and threading edge dislocations (TEDs) have been found to reduce the carrier lifetime and increase the leakage current of power devices based on 4H-SiC. − Meanwhile, basal plane dislocations (BPDs) have been identified as the origin of the expansion of a single Shockley stacking fault, which is responsible for bipolar degradation. , The detrimental effect of BPDs can be relieved by promoting the transition from BPDs to TEDs during the homoepitaxy of 4H-SiC. , However, over 95% threading dislocations (TDs) are replicated from 4H-SiC substrates to 4H-SiC epitaxial films, which pushes forward a great demand to reduce the density of TDs in 4H-SiC substrates.…”

Section: Introductionmentioning

confidence: 99%

Nucleation of Threading Dislocations in 4H-SiC at Early Physical-Vapor-Transport Growth Stage

Shao

Chen³

et al. 2023

Crystal Growth & Design

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In this work, we identify the nucleation mechanism of threading dislocations (TDs) associated with stacking faults (SFs) and 15R-SiC at the early growth stage of 4H-SiC single crystals grown by the physical vapor transport (PVT) technology. By combining molten KOH etching and photochemical etching, we successfully reveal etch pits of TDs and linear etch patterns of SFs on the (112̅0) surface of 4H-SiC single crystals. Systematic investigations based on transmission electron microscopy (TEM) observations and Raman analysis indicate that the Si–C bilayer stacking sequence of SFs is (3, 2) in Zhdanov’s notation. The accumulation of SFs (3, 2) gives rise to the polymorph fluctuation and thus the formation of 15R-SiC at the early PVT growth stage of 4H-SiC single crystals. Quantitative stress analyses indicate that the strain field distributions along the SFs (3, 2) and the 15R-/4H-SiC interfaces are inhomogeneous, which give rise to the nucleation of TDs and low-angle grain boundaries (LAGBs), respectively. The nucleation of LAGBs releases the high stress at the 15R-/4H-SiC interface, which facilities the following 4H-SiC single-crystal growth. Our work indicates that the avoidance of polymorph fluctuation is important to the reduction of TDs at the early growth stage of PVT-grown 4H-SiC single crystals.

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Structural analysis of double-layer Shockley stacking faults formed in heavily-nitrogen-doped 4H-SiC during annealing

Cited by 23 publications

References 37 publications

Origin and Generation Process of a Triangular Single Shockley Stacking Fault Expanding from the Surface Side in 4H-SiC PIN Diodes

Origin and Generation Process of a Triangular Single Shockley Stacking Fault Expanding from the Surface Side in 4H-SiC PIN Diodes

Single Shockley stacking fault expansion from immobile basal plane dislocations in 4H-SiC

Nucleation of Threading Dislocations in 4H-SiC at Early Physical-Vapor-Transport Growth Stage

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