Vacancies In Electron Irradiated 6H-SiC

Temperature Interval ◽

Paramagnetic Resonance ◽

Carbon Vacancy ◽

Electron Paramagnetic ◽

Major Reduction ◽

AbstractAnnealing of electron irradiated bulk n-type 6H-SiC has shown that neutral carbon vacancies and neutral silicon vacancies undergo a major reduction in concentration in the 20–200 °C temperature interval after which only slight changes occur up to 1200 °C. The experiments suggest that the positively charged carbon vacancy, detected by electron paramagnetic resonance, constitutes only a small fraction of all carbon vacancies.

Electron Paramagnetic Resonance Study of Carbon Antisite-Vacancy Pair in p-Type 4H-SiC

10.4028/www.scientific.net/msf.556-557.453 ◽

2007 ◽

Vol 556-557 ◽

pp. 453-456 ◽

Cited By ~ 5

Author(s):

T. Umeda ◽

Norio Morishita ◽

Takeshi Ohshima ◽

Hisayoshi Itoh ◽

Junichi Isoya

Keyword(s):

Electron Irradiation ◽

Electron Paramagnetic Resonance Study ◽

Dangling Bond ◽

Charged State ◽

Paramagnetic Resonance ◽

Vacancy Pair ◽

P Type ◽

Electron Paramagnetic ◽

Carbon antisite-vacancy pair (CSiVC) is a fundamental defect in SiC, and is theoretically predicted to be very stable in p-type materials. However, this pair was found only in the form of a negatively charged state (i.e., the SI5 center = CSiVC −) in n-type and semi-insulating 4H-SiC, and yet, its presence has not been shown in p-type SiC. In this report, we present the first EPR observation on positively charged CSiVC pairs in p-type 4H-SiC. By carefully examining p-type samples after electron irradiation, we found a pair of new defects with C3v and C1h symmetries. They correspond to “c-axial” pairs (C3v) and “basal” pairs (C1h) of CSiVC +, respectively. The positively charged pairs are characterized by a strong 13C hyperfine interaction due to a dangling bond on a carbon antisite (CSi), which is successfully resolved for the c-axial pairs.

Intrinsic Defects in HPSI 6H-SiC: an EPR Study

10.4028/www.scientific.net/msf.600-603.381 ◽

2008 ◽

Vol 600-603 ◽

pp. 381-384 ◽

Cited By ~ 4

Author(s):

Patrick Carlsson ◽

Nguyen Tien Son ◽

Björn Magnusson ◽

Anne Henry ◽

Erik Janzén

Keyword(s):

Vapor Deposition ◽

Thermal Activation ◽

Chemical Vapor ◽

Paramagnetic Resonance ◽

Intrinsic Defects ◽

Annealing Behavior ◽

Carbon Vacancy ◽

The Stability ◽

High-purity, semi-insulating 6H-SiC substrates grown by high-temperature chemical vapor deposition were studied by electron paramagnetic resonance (EPR). The carbon vacancy (VC), the carbon vacancy-antisite pair (VCCSi) and the divacancy (VCVSi) were found to be prominent defects. The (+|0) level of VC in 6H-SiC is estimated by photoexcitation EPR (photo-EPR) to be at ~ 1.47 eV above the valence band. The thermal activation energies as determined from the temperature dependence of the resistivity, Ea~0.6-0.7 eV and ~1.0-1.2 eV, were observed for two sets of samples and were suggested to be related to acceptor levels of VC, VCCSi and VCVSi. The annealing behavior of the intrinsic defects and the stability of the SI properties were studied up to 1600°C.

The Carbon Vacancy Related EI4 Defect in 4H-SiC

10.4028/www.scientific.net/msf.645-648.399 ◽

2010 ◽

Vol 645-648 ◽

pp. 399-402 ◽

Cited By ~ 1

Author(s):

Nguyen Tien Son ◽

Patrick Carlsson ◽

Junichi Isoya ◽

Norio Morishita ◽

Takeshi Ohshima ◽

...

Keyword(s):

High Purity ◽

Room Temperature ◽

Paramagnetic Resonance ◽

Annealing Behaviour ◽

Carbon Vacancy ◽

Epr Signal ◽

Electron paramagnetic resonance (EPR) was used to study high-purity semi-insulating 4H-SiC irradiated with 2 MeV electrons at room temperature. The EPR signal of the EI4 defect was found to be dominating in samples irradiated and annealed at ~750°C. Additional large-splitting 29Si hyperfine (hf) lines and also other 13C and 29Si hf structures were observed. Based on the observed hf structures and annealing behaviour, the complex between a negative carbon vacancy-carbon antisite pair (VCCSi–) and a distance positive carbon vacancy ( ) is tentatively proposed as a possible model for the EI4 defect.

Deep Level Point Defects in Semi-Insulating SiC

10.4028/www.scientific.net/msf.527-529.517 ◽

2006 ◽

Vol 527-529 ◽

pp. 517-522 ◽

Cited By ~ 5

Author(s):

Mary Ellen Zvanut ◽

Won Woo Lee ◽

Hai Yan Wang ◽

W.C. Mitchel ◽

William D. Mitchell

Keyword(s):

Point Defects ◽

Deep Level ◽

High Resistivity ◽

Temperature Dependent ◽

Paramagnetic Resonance ◽

Carbon Vacancy ◽

Device Applications ◽

Electron Paramagnetic ◽

Epr Experiments ◽

The high resistivity of SiC required for many device applications is achieved by compensating residual donors or acceptors with vanadium or intrinsic defects. This work addresses the defect levels of substitutional vanadium and the positively charged carbon vacancy (VC +) in semiinsulating (SI) SiC. After reviewing the earlier studies related to both defects, the paper focuses on temperature-dependent Hall measurements and photo-induced electron paramagnetic resonance (EPR) experiments of 4H and 6H SI SiC. In vanadium-doped samples, a V3+/4+ level near Ec-1.1 eV (4H) and Ec-0.85 eV (6H) is estimated by a comparison of dark EPR spectra and the activation energy determined from the Hall data, assuming that vanadium controls the Fermi level. In high purity semiinsulating substrates, analysis of time-dependent and steady-state photo-EPR data suggests that the plus-to-neutral transition of the carbon vacancy involves a structural relaxation of about 0.6 eV.

Intrinsic Defects in Semi-Insulating SiC: Deep Levels and their Roles in Carrier Compensation

10.4028/www.scientific.net/msf.556-557.465 ◽

2007 ◽

Vol 556-557 ◽

pp. 465-468 ◽

Cited By ~ 4

Author(s):

Nguyen Tien Son ◽

Patrick Carlsson ◽

Björn Magnusson ◽

Erik Janzén

Keyword(s):

High Purity ◽

Thermal Activation ◽

Activation Energies ◽

Deep Levels ◽

Paramagnetic Resonance ◽

Intrinsic Defects ◽

Carbon Vacancy ◽

Reported Data ◽

Vacancies, divacancies and carbon vacancy-carbon antisite pairs are found by electron paramagnetic resonance (EPR) to be dominant defects in high-purity semi-insulating (HPSI) 4HSiC substrates having different thermal activation energies of the resistivity ranging from ~0.8 eV to ~1.6 eV. Based on EPR results and previously reported data, the energy positions of several acceptor states of the vacancies and vacancy-related complexes are estimated. These deep levels are suggested to be associated to different thermal activation energies and responsible for the semiinsulating behaviour in HPSI SiC substrates. Their role in carrier compensation is discussed.

Temperature Independent Isotropic EPR Spectra of [(CH3)4N]2MnCl4 and [(CH3)4N]2FeCl4 Single Crystals

Zeitschrift für Naturforschung A ◽

10.1515/zna-1999-8-920 ◽

1999 ◽

Vol 54 (8-9) ◽

pp. 557-558 ◽

Cited By ~ 3

Author(s):

F. Köksal ◽

Ş. Bahadir ◽

E. Başaran ◽

Y. Yerli

Keyword(s):

Single Crystals ◽

Temperature Interval ◽

Epr Spectra ◽

Hindered Rotation ◽

Paramagnetic Resonance ◽

Electron paramagnetic resonance of [(CH3)4N]2MnCl4 and [(CH3)4N]2FeCl4 single crystals was studied between 20 and 400 K. The peak-to-peak derivative linewidths of these crystals seem not to change in this temperature interval and approximately 100 mT for [(CH3)4N]2MnCl4 and ~20 mT for [(CH3)4N]2FeCl4 .The spectra were found to be isotropic, with g = 2.0039 for [(CH3)4N]2MnCl4 and g = 2.0042 for [(CH3)4N]2FeCl4 .This temperature independence is attributed to isotropic strong ex-change interactions of Mn2- and Fe2+ nuclei, and it seems that hindered rotation of the MnCl42- and FeCl42- tetrahedra does not occur in this temperature interval.

Photoexcitation-electron-paramagnetic-resonance studies of the carbon vacancy in 4H-SiC

Applied Physics Letters ◽

10.1063/1.1522822 ◽

2002 ◽

Vol 81 (21) ◽

pp. 3945-3947 ◽

Cited By ~ 62

Author(s):

N. T. Son ◽

B. Magnusson ◽

E. Janzén

Keyword(s):

Paramagnetic Resonance ◽

Carbon Vacancy ◽

Characterization of Starburst Dendrimers by Electron Paramagnetic Resonance. 2. Positively Charged Nitroxide Radicals of Variable Chain Length Used as Spin Probes

Journal of the American Chemical Society ◽

10.1021/ja00120a022 ◽

1995 ◽

Vol 117 (15) ◽

pp. 4387-4398 ◽

Cited By ~ 64

Author(s):

M. Francesca Ottaviani ◽

Eleonora Cossu ◽

Nicholas J. Turro ◽

Donald A. Tomalia

Keyword(s):

Chain Length ◽

Spin Probes ◽

Nitroxide Radicals ◽

Paramagnetic Resonance ◽

Electron Paramagnetic ◽

Deep Levels Responsible for Semi-Insulating Behavior in Vanadium-Doped 4H-SiC Substrates

10.4028/www.scientific.net/msf.600-603.401 ◽

2008 ◽

Vol 600-603 ◽

pp. 401-404

Author(s):

Nguyen Tien Son ◽

Patrick Carlsson ◽

Andreas Gällström ◽

Björn Magnusson ◽

Erik Janzén

Keyword(s):

Activation Energy ◽

Thermal Activation ◽

Activation Energies ◽

Thermal Activation Energy ◽

Deep Levels ◽

Paramagnetic Resonance ◽

Intrinsic Defects ◽

Carbon Vacancy ◽

Semi-insulating (SI) 4H-SiC substrates doped with vanadium (V) in the range 5.5×1015 –1.1×1017 cm–3 were studied by electron paramagnetic resonance. We show that only in heavily V-doped 4H-SiC vanadium is responsible for the SI behavior, whereas in moderate V-doped substrates with the V concentration comparable or slightly higher than that of the shallow N donor or B acceptor, the SI properties are thermally unstable and determined by intrinsic defects. The results show that the commonly observed thermal activation energy Ea~1.1 eV in V-doped 4H-SiC, which was previously assigned to the single acceptor V4+/3+ level, may be related to deep levels of the carbon vacancy. Carrier compensation processes involving deep levels of V and intrinsic defects are discussed and possible thermal activation energies are suggested.