Photoluminescence Study of Radiation-Enhanced Dislocation Glide in 4H-SiC

Hirano, Rii; Sato, Yuki; Tsuchida, Hidekazu; Tajima, Michio; Itoh, Kohei M.; Maeda, Koji

doi:10.1143/apex.5.091302

Cited by 26 publications

(27 citation statements)

References 14 publications

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“…18 The motion of geometrical kink was also enhanced on those parts of the PD which were not irradiated, which was clearly shown in our experiments. Therefore, the enhancement of kink migration can be induced by carriers diffusing in the crystal from the irradiated area.…”

Section: Discussionsupporting

confidence: 78%

“…13,17 Hirano et al recently claimed that the mechanism of REDG in 4H-SiC is not REDR but the photoionization of dislocations by laser illumination, based on their experiments. 18 However, there are a few research reports on the REDG effects of PD in 4H-SiC, and many fundamental areas remain to be explored.…”

Section: Introductionmentioning

confidence: 99%

“…Previous research on SSF expansion or PD motion often employed imaging methods using electroluminescence, 11 photoluminescence, 14,18,19 cathodoluminescence, 20 or electronbeam-induced current. 20,21 In this paper, we report the observation of SSFs using secondary electron images, which is the most common mode of scanning electron microscopy (SEM) operation.…”

Section: Introductionmentioning

confidence: 99%

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Expansion of Shockley stacking fault observed by scanning electron microscope and partial dislocation motion in 4H-SiC

Yamashita

Nakata

Nishikawa

et al. 2018

Journal of Applied Physics

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We studied the dynamics of the expansion of a Shockley-type stacking fault (SSF) with 30° Si(g) partial dislocations (PDs) using a scanning electron microscope. We observed SSFs as dark lines (DLs), which formed the contrast at the intersection between the surface and the SSF on the (0001) face inclined by 8° from the surface. We performed experiments at different electron-beam scanning speeds, observing magnifications, and irradiation areas. The results indicated that the elongation of a DL during one-frame scanning depended on the time for which the electron beam irradiated the PD segment in the frame of view. From these results, we derived a formula to express the velocity of the PD using the elongation rate of the corresponding DL during one-frame scanning. We also obtained the result that the elongation velocity of the DL was not influenced by changing the direction in which the electron beam irradiates the PD. From this result, we deduced that the geometrical kink motion of the PD was enhanced by diffusing carriers that were generated by the electron-beam irradiation.

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Section: Discussionsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Expansion of Shockley stacking fault observed by scanning electron microscope and partial dislocation motion in 4H-SiC

Yamashita

Nakata

Nishikawa

et al. 2018

Journal of Applied Physics

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“…The mechanisms that have been presented to explain the expansion of SSFs under minority carrier injection – and their contraction under annealing above 300 °C 20–22 – are based on this electronic driving force. Two groups proposed mechanisms that are fundamentally not too different and depend on a net reduction of energy of a crystal by faulting (However, see the recent reports by Ohno et al 23 and Hirano et al 24.) Taking the total energy in a crystal to consist of a structural component (positive) and an electronic component (negative), the latter is usually much less than the former and hence a structurally faulted crystal generally has a higher energy than a perfect defect‐free crystal.…”

Section: Discussionmentioning

confidence: 99%

The concept of quasi‐Fermi level and expansion of faulted loops in SiC under minority carrier injection

Pirouz

2012

Physica Status Solidi (a)

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pirouz.pirouz@case.edu, Phone: þ1 216 368 6486, Fax: þ1 216 368 3209Degradation of 4H-SiC PiN diodes -a rapid increase in the forward voltage drop with operation time -has been a focus of research since it was first reported over a decade ago. It was soon discovered that associated with this degradation is a rapid increase in the number and extent of intrinsic stacking faults (SFs) in SiC. Further research showed that the expansion of SFs is due to the injection of electron-hole pairs (ehps) in the active region of the device under forward biasing. This effect indicated that recombination-induced dislocation glide -a phenomenon that was known to occur in many other semiconductors and in SiC -may play an important role in enhancing the motion of the leading partial dislocations and thus in expanding SFs in PiN diodes operated under forward bias conditions. This was later supported by enhanced nucleation and expansion of SFs by bandgap optical excitation in virginal SiC crystals itself -whether the material was of the 4H or 6H polytyperather than in forward-biased SiC diodes. At the same time, we used the concept of quasi-Fermi energy -as the transient value of the electron population during excited states of 4H-or 6H-SiC -to explain the driving force for expansion of SFs. Recently, Caldwell et al. have used this concept to develop various experimental observations that have been made on these diodes, including SF expansion under forward biasing, saturation of the maximum forward voltage drift, annealinginduced contraction of SFs so generated and consequent drift recovery of the forward voltage drop. In this paper, we expand the concept of quasi-Fermi level to get a better understanding of faulted loop expansion in 4H-SiC bipolar devices and in virgin 4H-and 6H-SiC crystals.

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“…This phenomenon is called as forward characteristic degradation. Even in the cases without pn-junction, when light is irradiated by a photoluminescence (PL) device or electron beam is irradiated by a scanning electron microscope (SEM) on the epitaxy film, dislocations serve as locations for electron-hole recombination, the Si-core 30°b ottom dislocations glide, and consequently the area of the Shockley-type stacking faults enlarges [29][30][31][32]. These phenomena are called radiation (or recombination) enhanced dislocation glide (REDG) effect.…”

Section: Changes Of Dislocation Structure Through Redg Effectmentioning

confidence: 99%

Analysis of Dislocation Structures in 4H‐SiC by Synchrotron X‐Ray Topography

Matsuhata¹,

Yamaguchi²,

Sekiguchi

et al. 2016

Electrical Engineering Japan

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SUMMARY Current 4H‐SiC wafers contain certain amount of dislocations, stacking faults, and other lattice‐defects. These defect structures evolve during various processes for power device fabrication. It is very important to examine evolutions of dislocation structures during power device processes, as well as the effect of dislocations on performances of fabricated power devices. Since lattice defects can be observed at only subsurface regions selectively by Berg–Barrett X‐ray topography, we have applied this useful observation technique to 4H‐SiC technology to solve various technological issues. Appearances of scratch‐like surface morphology after epi‐film growth on very flat substrate surface by chemomechanically polish were examined by this technique, and the mechanism was discussed. Analyses of dislocation structure evolutions during epi‐film growth and also basal‐plane dislocation glide by recombination of electrons and holes were discussed. Effects of threading‐screw dislocations on reliability of MOS structures and on current leakage in pn‐junction under reversed bias condition were investigated and discussed. Various important suggestions for 4H‐Sic industries were obtained.

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Photoluminescence Study of Radiation-Enhanced Dislocation Glide in 4H-SiC

Cited by 26 publications

References 14 publications

Expansion of Shockley stacking fault observed by scanning electron microscope and partial dislocation motion in 4H-SiC

Expansion of Shockley stacking fault observed by scanning electron microscope and partial dislocation motion in 4H-SiC

The concept of quasi‐Fermi level and expansion of faulted loops in SiC under minority carrier injection

Analysis of Dislocation Structures in 4H‐SiC by Synchrotron X‐Ray Topography

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