| Autor: |
YANO, Hiroshi, UMEDA, Takahide, Kagoyama, Y., Okamoto, M., Yamasaki, T., Tajima, N., Nara, J., Ohno, T., Harada, S. |
| Jazyk: |
angličtina |
| Rok vydání: |
2019 |
| Předmět: |
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| Zdroj: |
Journal of applied physics. 125(6):065302 |
| ISSN: |
0021-8979 |
| Popis: |
We investigated a metal-oxide-semiconductor interface of dry-oxidized (0001¯) 4H-SiC, which was known as the most electrically deteriorated SiC MOSFET, by electrically detected magnetic resonance (EDMR) and observed a signal with an isotropic g factor (2.0024) and magnetic-field angular dependent signal widths. Judging from the g factor, the signal comes from sp2-bonded carbon clusters. In addition, we found that the angular dependence of EDMR signal widths was caused by two-dimensional dipolar broadening with exchange interaction between electron spins. However, the density of electron spins or carbon clusters was 5.4 × 1013 cm−2, which was not high enough for exchange interaction. Therefore, we propose inhomogeneous distribution of carbon clusters in the interface. At the interface, π* peaks from sp2-bonded carbon atoms were detected by electron energy loss spectroscopy. Scanning the electron beams along the interface revealed uneven existence of the π* peaks, which also proved that the sp2-bonded carbon atoms were distributed inhomogeneously in the interface. In addition, we found the formation of sp2-bonded carbon clusters at 4H-SiC(0001¯ )/SiO2 interfaces and interaction between π-conjugate electron spins on the carbon clusters by first principles calculation. Such carbon clusters generated electrically active states widely in the energy gap of 4H-SiC. The states result in the Fermi level pinning of the MOSFET. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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