Defect levels and types of point defects in high-purity and vanadium-doped semi-insulating 4H–SiC
| Autor: | V. V. Konovalov, William C. Mitchel, G. Landis, William D. Mitchell, Mary Ellen Zvanut, Haiyan Wang |
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| Rok vydání: | 2004 |
| Předmět: |
Materials science
Condensed matter physics Doping Analytical chemistry General Physics and Astronomy Vanadium chemistry.chemical_element Activation energy Crystallographic defect law.invention chemistry Electrical resistivity and conductivity law Hall effect Vacancy defect Electron paramagnetic resonance |
| Zdroj: | Journal of Applied Physics. 96:5484-5489 |
| ISSN: | 1089-7550 0021-8979 |
| Popis: | Electron paramagnetic resonance (EPR) spectroscopy and photo-induced EPR are used to examine the point defects in vanadium-doped 4H–SiC and high-purity semi-insulating (HPSI) 4H–SiC grown by physical vapor transport. Both types of samples often exhibit a 1.1-eV activation energy, Ea, as extracted from the temperature-dependent Hall/resistivity measurements; however, different defects are related to the same Ea in each case. In the vanadium-doped wafers, the EPR data reveal both V4+ and V3+ in the same sample; thus, the 1.1-eV Hall activation energy is tentatively interpreted as the V3+∕4+ acceptor level. However, this conclusion cannot be confirmed because additional defects complicate the photoresponse of vanadium. The carbon vacancy, which is detected in all the HPSI wafers, exhibits a range of photothresholds similar to the various values measured for Ea. The photo-EPR and temperature-dependent Hall/resistivity measurements made before and after a 1600°C anneal suggest that several different types of nonuniformly distributed defects participate in compensation of the HPSI material and that annealing selectively removes those with different defect levels. |
| Databáze: | OpenAIRE |
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