| 1. |
- Zetterling, Carl-Mikael, et al.
(författare)
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Comparison of SiO2 and AlN as gate dielectric for SiC MOS structures
- 1998
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Ingår i: Materials Science Forum. - : Trans Tech Publications Inc.. - 0255-5476 .- 1662-9752. ; 264-268, s. 877-880
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Tidskriftsartikel (refereegranskat)abstract
- The electrical properties of silicon dioxide (thermal oxidation) and aluminum nitride (metal organic chemical vapor deposition) have been compared for use as gate dielectric for silicon carbide metal insulator semiconductor structures. High frequency capacitance voltage measurements at room temperature were used to investigate fixed charge and deep interface states. The deep interface states could be passivated with hydrogen if introduced during growth of silicon dioxide. Although results are promising for aluminum nitride, the morphology of the films grown so far do not allow a fair comparison with silicon dioxide.
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| 2. |
- Zetterling, Carl-Mikael, et al.
(författare)
-
Formation and high frequency CV-measurements of aluminum/aluminum nitride/6H silicon carbide structures
- 1996
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Ingår i: Materials Research Society Symposium - Proceedings. - San Francisco, CA, USA. ; , s. 667-672
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Konferensbidrag (refereegranskat)abstract
- Undoped single crystalline aluminum nitride films were grown by metal organic chemical vapor deposition (MOCVD) at 1200 °C. The precursors used were trimethylaluminum (TMA) and ammonia (NH3) in a hydrogen carrier flow, at a pressure of 10 Torr. Silicon carbide substrates of the 4H or the 6H polytype with an epilayer on the silicon face, were used to grow the 200 nm thick AlN films. Aluminum was evaporated and subsequently patterned to form MIS capacitors for high frequency (400 kHz) capacitance voltage measurements at room temperature. It was possible to measure the structure and characterize accumulation, depletion and deep depletion. However, it was not possible to invert the low doped SiC epilayer at room temperature. From an independent optical thickness measurement the relative dielectric constant of aluminum nitride was calculated to be 8.4. The films were stressed up to 50 Volts (2.5 MV/cm) without breakdown or excessive leakage currents. These results indicate the possibility to replace silicon dioxide with aluminum nitride in SiC field effect transistors.
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| 3. |
- Zetterling, Carl-Mikael, et al.
(författare)
-
Investigation of aluminum nitride grown by metal-organic chemical-vapor deposition on silicon carbide
- 1997
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 82:6, s. 2990-2995
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Tidskriftsartikel (refereegranskat)abstract
- Undoped single crystalline aluminum nitride films were grown on 4H and 6H SiC substrates using metal-organic chemical-vapor deposition at 1200°C. From in situ reflection high-energy electron diffraction, x-ray diffraction rocking curves, and cathodoluminescence spectra, the crystallinity of the films was confirmed. Atomic force microscopy showed that some films were substantially dominated by island growth, rather than step flow growth. Aluminum was evaporated to form metal-insulator-semiconductor (MIS) capacitors for high-frequency capacitance voltage measurements carried out at room temperature. Low leakage made it possible to measure the structures and characterize accumulation, depletion, deep depletion, and, in some cases, inversion. From independent optical thickness measurements, the relative dielectric constant of aluminum nitride was confirmed at 8.4. The flatband voltage of the AlN MIS capacitors on p-type SiC was close to the theoretical value expected. The films were stressed up to 60 V (3 MV/cm) without breakdown, but excessive leakage currents (>0.1 A/cm2), probably dominated by grain-boundary conduction, shifted the flatband voltage of the capacitors. These results indicate the possibility of replacing silicon dioxide with aluminum nitride in SiC field effect transistors using insulated gates.
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