Abstract: We have simultaneously determined the carrier concentration, mobility, and thickness of
4H-SiC homo-epilayers with carrier concentration of 1016–1018 cm-3 from reflectance spectroscopy in
the wavenumber range of 20–2000 cm-1. The spectra at 20–100 cm-1 and at 80–2000 cm-1 were
measured by using the terahertz time domain spectrometer (THz-TDS) and the Fourier-transform
infrared (FTIR) spectrometer, respectively. A modified classical dielectric function (MDF) model
was employed for the curve fitting. We have compared the values of free carrier concentrations
estimated from the reflectance spectroscopy with the net doping concentrations obtained from C–V
measurements, and have discussed the validity of the electrical properties estimated from the
Abstract: We present the injection electroluminescence spectra in the temperature range 290-760 K
of 3C-SiC pn structure, which was fabricated by sublimation epitaxy in vacuum on 6H-SiC
substrate. The dominant emission band of injection electroluminescence (IEL) spectrum was
observed in the green region; at room temperature the IEL intensity outside the region of hν ≈ 2.0-
2.5 eV was less than 3% of that of the green peak. The peak parameters at room temperature are:
hνmax ≈ 2.32 eV, full width at half maximum w ≈ 100 meV. The green peak shifted in the longwave
direction with increasing temperature; the hνmax (T) dependence was linear with the slope of -
1.3x10-4 eV/K. Both the IEL intensity of the green peak at hνmax and band width w increased upon
heating. The w(T) dependence was linear with the slope of 4.6x10-4 eV/K; intensity increased with
the activation energy of 70 meV. The green IEL band can be considered to be due to the free
exciton annihilation or to the band-band recombination and edge IEL increasing with rising
temperature can be explained by the nonequilibrium charge carriers lifetime increasing.
Abstract: In the 6H-SiC p+-n--n+ junction the effect of the premature breakdown has been revealed.
This effect stimulated by the small temperature increase and illumination by light with energy
greater than the bandgap energy of 6H-SiC. The breakdown field appears to be 20% less than the
intrinsic breakdown field in these structures.
Abstract: The paper presents the results of a quantitative theoretical calculation concerning the shift
and the splitting of the ground-state manifold of the nitrogen donor in 4H-SiC under uniform
electric field. Two cases are distinguished corresponding to a field applied parallel and
perpendicular to the crystal axis. A comparison with the phosphorus donor in Si is carried out.
Abstract: The existence of point defects is one of the key problems in SiC technology. Combined
experimental and theoretical investigations can be successful in identification of point defects.
We report the identification of a basic intrinsic defect in p-type SiC. In addition, we predict the
existence of interstitial-related electrically active defects which may be detected by experimental
Abstract: We have investigated several aluminum-related complexes in 4H-SiC by ab initio
supercell calculations. The binding energies of the defects predict high thermal stability and
complex formation between aluminum and carbon interstitials in SiC. We show that the carbon
vacancy can be attached to a shallow the aluminum acceptor and form a very stable defect.
We also found that aluminum interstitial forms stable and metastable complexes with one or
two carbon interstitials. The possible relation of these defects to the recently found aluminum-
related DLTS centers is also discussed.
Abstract: The SI-5 electron-paramagnetic-resonance (EPR) centre is a dominant defect in some
high-purity semi-insulating (HPSI) SiC substrates and has recently been shown to originate from
the negatively charged carbon vacancy-carbon antisite pair (VC
Si C ). In this work, photoexcitation
EPR (photo-EPR) was used for determination of the energy position of deep acceptor levels of
VCCSi in 4H-SiC. Our photo-EPR measurements in slightly n-type material show an increase of the
EPR signal of VC
Si C for photon energies from ~0.8 eV to ~1.3 eV. Combining the data from EPR,
deep level transient spectroscopy and supercell calculations we suggest that the (1–|2–) levels of the
different configurations of the defect are located in the range ~0.8-1.1 eV below the conduction
Abstract: 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.
Abstract: Impurity atoms in a high-purity semi-insulating 4H-SiC substrate fabricated by sublimation
and an n-type 3C-SiC substrate fabricated by Chemical Vapor Deposition (CVD) were evaluated by
neutron activation analysis. Cr, Fe, Zn, As, Br, Mo, Sb, Eu, Yb, Hf, Ta, W and Au atoms were
detected in the 4H-SiC fabricated by sublimation. In the 3C-SiC fabricated by CVD, Cr, Zn, As, Br,
Mo, Sb, La Sm and Hf atoms were found. The concentration of these atoms tends to decrease with
increasing atomic number.
Abstract: Nitrogen doped 4H-SiC epitaxial layers grown by hot-wall chemical vapor deposition
were investigated by Deep Level Transient Spectroscopy after irradiation with 6 MeV electrons at
room temperature. This study is focusing on the influence of nitrogen doping and C/Si ratio on the
behaviour of the Z1,2 and EH6,7 levels which occur in already as-grown material but are substantially
enhanced by electron and ion irradiation. It was found that both the Z1,2 and EH6,7 concentrations
increase with both the nitrogen doping and the C/Si ratio. However, while the Z1,2 concentration
increases during post-irradiation thermal treatment the opposite holds for the EH6,7 level especially
in silicon rich samples. On the basis of these results, the influence of carbon and nitrogen on the
formation of the Z1,2 complex is reconfirmed and a possible identity of the EH6,7 defect is discussed.