| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Jacobson, H., et al.
(författare)
-
Properties and origins of different stacking faults that cause degradation in SiC PiN diodes
- 2004
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 95:3, s. 1485-1488
-
Tidskriftsartikel (refereegranskat)abstract
- Different properties of the reported stacking faults (SFs) and that both these types of SF are present in the material after electrical degradation of pin diodes are shown. One is caused by perfect dislocations, deflected or misfit dislocation that had dissociated into two partial dislocations. The partials are assumed to be close to each other with a separation below the detection limit of the SWBT measurements. Thus, enough energy is provided and the leading partial moves away from the other partial and forms the extended SF.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Nguyen, Son Tien, 1953-, et al.
(författare)
-
Hole effective masses in 4H SiC
- 2000
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:16
-
Tidskriftsartikel (refereegranskat)abstract
- Optically detected cyclotron resonance (ODCR) at X-band frequency (~9.23 GHz) was used to study hole effective masses in 4H SiC. In addition to the known ODCR signal related to the cyclotron resonance (CR) of electrons we have observed an ODCR peak at a higher magnetic field, which is attributed to the CR of holes. In the vicinity of the maximum of the uppermost valence band, the constant energy surface can be considered as an ellipsoid with the principal axis along the c axis and the effective masses of the holes were determined as mh? = (0.66▒0.02)m0 and mh?=(1.75▒0.02)m0. The influence of the polaron coupling effect on the effective mass values in 4H SiC is discussed. ⌐ 2000 The American Physical Society.
|
|
| 11. |
|
|
| 12. |
- Nguyen, Son Tien, 1953-, et al.
(författare)
-
Optically detected magnetic resonance studies of intrinsic defects in 6H-SiC
- 1999
-
Ingår i: Semiconductor Science and Technology. - 0268-1242 .- 1361-6641. ; 14:12, s. 1141-1146
-
Tidskriftsartikel (refereegranskat)abstract
- Optically detected magnetic resonance (ODMR) was used for study of defects in n-type 6H-SiC. Four ODMR spectra related to spin S = 1 centres were observed. Two of these centres, labelled a and b, have a trigonal symmetry with the symmetry axis along the c-axis of the hexagonal crystal. For the other two centres, labelled c and d, the symmetry is lower (C1h) and the principal axis z of the g- and D-tensor is about 71 degrees off the c-axis. Based on the symmetry axes, the annealing behaviour and the intensity, these spectra are suggested to originate from different configurations of the paired centre between a silicon vacancy and a nearest-neighbour point defect (either a carbon vacancy or a silicon antisite), occupying different inequivalent sites in the 6H-SiC. These defects are non-radiative and act as efficient recombination channels in the material.
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
- Sörman, E., et al.
(författare)
-
Silicon vacancy related defect in 4H and 6H SiC
- 2000
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:4, s. 2613-2620
-
Tidskriftsartikel (refereegranskat)abstract
- We report on an irradiation-induced photoluminescence (PL) band in 4H and 6H SiC and the corresponding optically detected magnetic resonance (ODMR) signals from this band. The deep PL band has the same number of no-phonon lines as there are inequivalent sites in the respective polytype. These lines are at 1352 and 1438 meV in the case of 4H and at 1366, 1398, and 1433 meV in the case of 6H. The intensity of the PL lines is reduced after a short anneal at 750░C. ODMR measurements with above-band-gap excitation show that two spin-triplet (S=1) states with a weak axial character are detected via each PL line in these bands. One of these two triplet states can be selectively excited with the excitation energy of the corresponding PL line. These triplet signals can therefore be detected separately and only then can the well documented and characteristic hyperfine interaction of the silicon vacancy in SiC be resolved. Considering the correlation between the irradiation dose and the signal strength, the well established annealing temperature and the characteristic hyperfine pattern, we suggest that this PL band is related to the isolated silicon vacancy in 4H and 6H SiC. The spin state (S=1) implies a charge state of the vacancy with an even number of electrons. By combining the knowledge from complementary electron-spin resonance measurements and theoretical calculations we hold the neutral charge state for the strongest candidate. ⌐2000 The American Physical Society.
|
|
| 16. |
- Wagner, Matthias, 1969-, et al.
(författare)
-
Electronic structure of the neutral silicon vacancy in 4H and 6H SiC
- 2000
-
Ingår i: Physical review. B, Condensed matter and materials physics. - 2469-9950. ; 62:24, s. 16555-16560
-
Tidskriftsartikel (refereegranskat)abstract
- Detailed information about the electronic structure of the lowest-lying excited states and the ground state of the neutral silicon vacancy in 4H and 6H SiC has been obtained by high-resolution photoluminescence (PL), PL excitation (PLE), and Zeeman spectroscopy of both PL and PLE. The excited states and the ground states involved in the characteristic luminescence of the defect with no-phonon (NP) lines at 1.438 and 1.352 eV in 4H SiC and 1.433, 1.398, and 1.368 eV in 6H SiC are shown to be singlets. The orbital degeneracy of the excited states is lifted by the crystal field for the highest-lying NP lines corresponding to one of the inequivalent lattice sites in both polytypes, leading to the appearance of hot lines at slightly higher energies. Polarization studies of the NP lines show a different behavior for the inequivalent sites. A comparison of this behavior in the two polytypes together with parameters from spin resonance studies provides useful hints for the assignment of the no-phonon lines to the inequivalent sites. In strained samples an additional fine structure of the NP lines can be resolved. This splitting may be due to strain variations in the samples.
|
|
| 17. |
|
|
| 18. |
- Wagner, Matthias, 1969-, et al.
(författare)
-
Zeeman spectroscopy of the neutral silicon vacancy in 6H and 4H SiC
- 1999
-
Ingår i: Physica B. Vol. 273-274. - : Elsevier. ; , s. 663-
-
Konferensbidrag (refereegranskat)abstract
- High-resolution photoluminescence (PL) and PL excitation (PLE) spectroscopy has been employed to reveal the electronic structure of the neutral silicon vacancy in 6H and 4H SiC. The defect gives rise to characteristic PL emissions with three no-phonon lines in 6H SiC and two in 4H SiC at around 1.4 eV. All of the no-phonon lines are shown to arise from transitions between singlet (S=0) excited states and singlet ground states. Nevertheless, optically detected magnetic resonance (ODMR) signals typical for a spin triplet (S=1) configuration can be obtained when monitoring the emission under resonant excitation. This observation can be explained by non-radiative recombination via a lower lying excited triplet state. In strained samples all no-phonon PL lines are split into a series of lines. For the highest energy lines the main splitting can be attributed to lifting of the orbital degeneracy of the excited states, the additional broadening or splitting is probably due to a strain distribution in the samples.
|
|
| 19. |
- Zolnai, Z, et al.
(författare)
-
Annealing behavior of the carbon vacancy in electron-irradiated 4H-SiC
- 2004
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 96:4, s. 2406-2408
-
Tidskriftsartikel (refereegranskat)abstract
- The annealing behavior of the positively charged carbon vacancy in electron-irradiated 4H-SiC was studied. Electron paramagnetic resonance was used for the purpose of analysis. It was found that around 1000 °C, the EPR signal of the defect starts decreasing. Clear ligand hyperfine structure was also observed after annealing at 1350 °C. Results show that the EI6 center may be the positively charged carbon vacancy at the hexagonal lattice site of 4H-SiC.
|
|
| 20. |
|
|
