EPR Study of Carbon Vacancy-Related Defects in Electron-Irradiated 6H-SiC

Bratus, V. Ya.; Makeeva, I.N.; Okulov, S. M.; Petrenko, T.L.; Petrenko, Taras; Bardeleben, H. J. von

doi:10.4028/www.scientific.net/msf.353-356.517

Cited by 20 publications

(9 citation statements)

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“…Intrinsic defects have been studied intensively in SiC, [1][2][3][4][5][6][7][8][9][10][11][12][13][14] which is a popular wide-band-gap material for high-power and high-temperature microelectronics. 15 Recently, deeplevel intrinsic defects have attracted considerable interest as potential electron-hole traps suitable for compensation of residual impurities in high-quality SiC.…”

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confidence: 99%

240 GHz electron paramagnetic resonance studies of intrinsic defects in as-grown4HSiC

2003

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240 GHz electron paramagnetic resonance ͑EPR͒ measurements of as-grown nominally semi-insulating 4H SiC detected two well-separated centers ID1 and ID2. The EPR parameters of ID1 and ID2 coincide with that of EI5 and EI6 centers previously detected in 2-MeV electron-irradiated p-type 4H SiC:Al by 95 GHz EPR ͑Son et al.͒. The defects in irradiated material were assigned to a positively charged carbon vacancy ͑EI5͒ and silicon antisite ͑EI6͒, respectively. Increased separation between the two centers at 240 GHz and the absence of additional radiation-induced spectral lines in the as-grown, unirradiated SiC facilitated analysis of the defect structure. Our data support that the ID1 center is a carbon vacancy-related defect, but is not consistent with the assignment of the ID2 center to a silicon antisite. The ID2 spectrum is best fit as another carbon vacancyrelated defect. Illumination with light below 1400 nm quenched both ID1 and ID2 simultaneously, suggesting that the defect energy levels are nearly the same.Intrinsic defects have been studied intensively in SiC, 1-14 which is a popular wide-band-gap material for high-power and high-temperature microelectronics. 15 Recently, deeplevel intrinsic defects have attracted considerable interest as potential electron-hole traps suitable for compensation of residual impurities in high-quality SiC. 16 The presence of a deep intrinsic defect ͑ID͒ capable of exchanging charge with boron-nitrogen impurities has been demonstrated by X-band (ϳ9.5 GHz) electron paramagnetic resonance ͑EPR͒ in asgrown nominally semi-insulating 4H SiC produced by Cree Inc. with vanadium-free technology. 13,14 The X-band EPR spectrum of ID consists of two barely resolved lines ID1 and ID2. These coincide with the X-band spectra of EI5/EI6 and Ky2/Ky3 centers detected in 2-MeV electron-irradiated p-type 4H, 6H SiC:Al ͑Refs. 7-9͒ and 6H SiC:B ͑Refs. 11 and 12͒, respectively. Higher frequency W-band ͑95 GHz͒ EPR resolved EI5 and EI6 centers, which were assigned to a positively charged carbon vacancy and silicon antisite, respectively. 7-10 The assignment of each center was based on the analysis of the intensities of hyperfine ͑HF͒ satellite lines originating from the interaction of an electron spin (S ϭ1/2) with a 29 Si magnetic nuclei (Iϭ1/2). At the same time, density functional theory ͑DFT͒ calculations using small 4H SiC clusters suggested that EI5/Ky2 and EI6/Ky3 centers may represent two positively charged carbon vacancies at the quasicubic and hexagonal lattice sites of 4H SiC. 17 In this report, we present 240 GHz EPR measurements of the intrinsic defects in as-grown high-purity 4H SiC. Using a microwave frequency of 240 GHz, the ID1 and ID2 centers were well resolved, and it was determined that their EPR parameters are the same as those of EI5 and EI6 obtained at 95 GHz. The well-separated spectral lines combined with the lack of additional radiation-induced signals facilitated analysis of the defect structure.High-purity as-grown nominally semi-insulating ͑0001͒ 4H SiC wafers, grown by the...

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confidence: 99%

240 GHz electron paramagnetic resonance studies of intrinsic defects in as-grown4HSiC

2003

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“…Based on the ligand HF structure, the symmetry and the observation in ptype irradiated material, the EI5 center was identified as the isolated carbon vacancy in the positive charge state (V + C ) [46,47]. At the same time, Bratus et al [48] also came to the same conclusion about the Ky2 center in 6H-SiC, which is identical to EI5. In a later study, Bratus et al [49] assigned also the Ky1 and Ky3 (identical to the EI6 signal) to V + C at the other cubic site and hexagonal site, respectively, in 6H-SiC.…”

Section: Carbon Vacancymentioning

confidence: 90%

“…Recently, the EI5 center in 4H-and 6H-SiC [46,47] was identified as V + C . The same center in 6H-SiC, labelled Ky1, was also attributed to V + C by Bratus et al [48,49]. Using low-energy electron irradiation, Steeds et al [50] were able to determine the displacement energies for C and Si atoms to be about 100 keV and 250 keV, respectively.…”

Section: Introductionmentioning

confidence: 90%

Electronic Structure of Deep Defects in SiC

et al. 2004

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“…17,18 The photo-EPR data reveal that the ID-1 center photo-exchanges charge with both nitrogen and boron impurities. Each type can be defined by the presence of a dominant feature: the nitrogen donor, boron acceptor, intrinsic defect (ID-1), or the absence of all these features.…”

Section: Discussionmentioning

confidence: 99%