| 11. |
- Hahn, S., et al.
(författare)
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Contact-Less Electrical Defect Characterization of Semi-Insulating 6H-SiC Bulk Material
- 2009
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Ingår i: Materials Science Forum Vols. 600-603. - : Trans Tech Publications. ; , s. 405-408
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Konferensbidrag (refereegranskat)abstract
- The novel technique microwave detected photo induced current transient spectroscopy (MD-PICTS) was applied to semi-insulating 6H-SiC in order to investigate the properties of inherent defect levels. Defect spectra can be obtained in the similar way to conventional PICTS and DLTS. However, there is no need for contacting the samples, which allows for non-destructive and spatially resolved electrical characterization. This work is focused on the investigation of semi-insulating 6H-SiC grown under different C/Si-ratios. In the corresponding MD-PICTS spectra several shallow defect levels appear in the low temperature range. However the peak assignment needs further investigation. Additionally different trap reemission dynamics are obtained for higher temperatures, which are supposed to be due to different compensation effects.
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| 12. |
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| 13. |
- Henry, Anne, 1959-, et al.
(författare)
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Growth of 4H-SiC Epitaxial Layers on 4° Off-axis Si-face substrates
- 2009
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Ingår i: Materials Science Forum, Vols. 615-617. - : Trans Tech Publications. - 9780878493340 ; , s. 81-84
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Konferensbidrag (refereegranskat)abstract
- CVD growth of epitaxial layers with a mirror like surface grown on 75 mm diameter 4° off-axis 4H SiC substrates is demonstrated. The effect of the C/Si ratio, temperature and temperature ramp up conditions is studied in detail. A low C/Si ratio of 0.4 and a temperature of 1530 °C is the best combination to avoid step bunching and triangular defects on the epitaxial layers. Using a low growth rate (about 3 µm/h) 6 μm thick, n-type doped epilayers were grown on 75 mm diameter wafers resulting in an RMS value of 0.7 nm and good reproducibility. 20 μm thick epitaxial layers with a background doping in the low 1014 cm-3 were grown with a mirror-like, defect-free surface. Preliminary results when using higher Si/H2 ratio (up to 0.4 %) and HCl addition are also presented: growth rate of 28 μm/h is achieved while keeping a smooth morphology.
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| 14. |
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| 15. |
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| 16. |
- Henry, Anne, 1959-, et al.
(författare)
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Single Crystal and Polycrystalline 3C-SiC for MEMS Applications
- 2009
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Ingår i: Materials Science Forum Vols. 615-617. - : Trans Tech Publications. - 9780878493340 ; , s. 625-628
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Konferensbidrag (refereegranskat)abstract
- Cantilever resonators have been fabricated from two types of materials, single crystal and polycrystalline 3C-SiC films. The films have been grown in a hot-wall chemical vapor deposition reactor on 100 mm diameter p-type boron-doped (100) Si wafer without rotation of the wafer. The crystal structure of the films have been accessed with X-ray diffraction. The cantilever devices have been fabricated using a one-step etch and release process; the beam length has been varied between 50 and 200 µm. Resonant frequencies in the range 110 KHz – 1.5 MHz and 50 – 750 KHz have been obtained for single crystal and polycrystalline SiC devices, respectively. Furthermore, the experimental resonance frequencies have been used to calculate the Young’s Modulus E for the two different types of SiC. The single crystal SiC, possessing a very high Young’s Modulus (446 GPa), should be an optimal material for RF-MEMS applications.
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| 17. |
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| 18. |
- Henry, Anne, 1959-, et al.
(författare)
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Titanium related luminescence in SiC
- 2006
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Konferensbidrag (refereegranskat)abstract
- We report on the luminescence spectra related to Ti impurity in 6H-SiC. The spectra depend strongly on the polarization. There are three families of PL lines. Phonon structure is observed containing both broad and sharp replicas. When the temperature increases extra lines appear at high energy. Time-resolved PL reveals a 0.1 ms long lifetime at 2 K.
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| 19. |
- Henry, Anne, 1959-, et al.
(författare)
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Titanium Related Luminescence in SiC
- 2009
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Ingår i: ICSCRM2007,2007. - Materials Science Forum, Vols. 600-603 : Trans Tech Publications. ; , s. 461-464
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Konferensbidrag (refereegranskat)abstract
- We report on the luminescence spectra related to Ti impurity in both 4H- and 6H-SiC polytypes. The spectrum depends strongly on the polarization. They are two families of lines in 4H and three in 6H. The main no-phonon line of each family is shown as a triplet and its phonon structure contains both sharp and broad replicas. The higher energy family has also extra lines at high energy appearing when the temperature increases. The spectra can be detected with excitation energy below the excitonic bandgap and even with excitation energy below the spectrum itself. Time-resolved photoluminescence reveals 0.1 ms long lifetime at low temperature.
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| 20. |
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