| 1. |
- Leerungnawarat, P., et al.
(författare)
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Via-hole etching for SiC
- 1999
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Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 17, s. 2050-2054
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Tidskriftsartikel (refereegranskat)abstract
- Four different F2-based plasma chemistries for high-rate etching of SiC under inductively coupled plasma (ICP) conditions were examined. Much higher rates (up to 8000 #x2009; #xc5; #x2009;min-1) were achieved with NF3 and SF6 compared with BF3 and PF5, in good correlation with their bond energies and their dissociation efficiency in the ICP source. Three different materials (Al, Ni, and indium #x2013;tin oxide) were compared as possible masks during deep SiC etching for through-wafer via holes. Al appears to produce the best etch resistance, particularly when O2 is added to the plasma chemistry. With the correct choice of plasma chemistry and mask material, ICP etching appears to be capable of producing via holes in SiC substrates. #xa9; 1999 American Vacuum Society.
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| 2. |
- Wang, J. J., et al.
(författare)
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High rate etching of SiC and SiCN in NF3 inductively coupled plasmas
- 1998
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 42:5, s. 743-747
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Tidskriftsartikel (refereegranskat)abstract
- Etch rates of ∌3,500 Å/min for 6H-SiC and ∌7,500 Å/min for SiC0.5N0.5 were obtained in inductively coupled plasmas with NF3-based chemistries. Similar etch rate trends were achieved with both NF3/O2 and NF3/Ar mixtures. The rates were strong functions of plasma composition, ion energy and ion fluxes, and were independent of conductivity type for SiC. Surface root-mean-square (RMS) roughness were 1-2 nm for etched SiC over a wide range of conditions indicating equi-rate removal of the SiFx and CFx etch products, but SiCN surfaces became extremely rough (RMS roughness > 20 nm) for F2-rich plasma conditions. The etched surfaces of SiC were chemically clean and stoichiometric, with small (<0.2 at%) quantities of N2- or F2- containing residues detected. © 1998 Elsevier Science Ltd. All rights reserved.
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| 3. |
- Wang, J. J., et al.
(författare)
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ICP etching of SiC
- 1997
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Ingår i: Materials Research Society Symposium - Proceedings. - Boston, MA, USA. ; , s. 177-183
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Konferensbidrag (refereegranskat)abstract
- A number of different plasma chemistries, including NF3/O2, SF6/O2, SF6/Ar, ICl, IBr, Cl2/Ar, BCl3/Ar and CH4/H2/Ar, have been investigated for dry etching of 6H and 3C-SiC in a Inductively Coupled Plasma tool. Rates above 2,000 angstroms·cm-1 are found with fluorine-based chemistries at high ion currents. Surprisingly, Cl2-based etching does not provide high rates, even though the potential etch products (SiCl4 and CCl4) are volatile. Photoresist masks have poor selectivity over SiC in F2-based plasmas under normal conditions, and ITO or Ni are preferred.
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| 4. |
- Wang, J. J., et al.
(författare)
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ICP etching of SiC
- 1998
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 42:12, s. 2283-2288
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Tidskriftsartikel (refereegranskat)abstract
- A number of different plasma chemistries, including NF3/O2, SF6/O2, SF6/Ar, ICl, IBr, Cl2/ Ar, BCl3/Ar and CH4/H2/Ar, have been investigated for dry etching of 6H and 3C-SiC in an inductively coupled plasma tool. Rates above 2000 Å cm-1 are found with fluorine-based chemistries at high ion currents. Surprisingly, Cl2-based etching does not provide high rates, even though the potential etch products (SiCl4 and CCl4) are volatile. Photoresist masks have poor selectivity over SiC in F2-based plasmas under normal conditions, and ITO or Ni is preferred. © 1998 Published by Elsevier Science Ltd. All rights reserved.
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| 5. |
- Wang, J. J., et al.
(författare)
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Inductively coupled plasma etching of bulk 6H-SiC and thin-film SiCN in NF3 chemistries
- 1998
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - 0734-2101 .- 1520-8559. ; 16:4, s. 2204-2209
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Tidskriftsartikel (refereegranskat)abstract
- A parametric study of the etching characteristics of 6H p+ and n+ SiC and thin-film SiC0.5N0.5 in inductively coupled plasma (ICP) NF3/O2 and NF3/Ar discharges has been performed. The etch rates in both chemistries increase monotonically with NF3 percentage and rf chuck power. The etch rates go through a maximum with increasing ICP source power, which is explained by a trade-off between the increasing ion flux and the decreasing ion energy. The anisotropy of the etched features is also a function of ion flux, ion energy and atomic fluorine neutral concentration. Indium-tin-oxide masks display relatively good etch selectivity over SiC (maximum of ∌70:1), while photoresist etches more rapidly than SiC. The surface roughness of SiC is essentially independent of plasma composition for NF3/O2 discharges, while extensive surface degradation occurs for SiCN under high NF3:O2 conditions. © 1998 American Vacuum Society.
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| 6. |
- Wang, J. J., et al.
(författare)
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Low damage, highly anisotropic dry etching of SiC
- 1998
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Ingår i: High Temperature Electronics Conference, 1998. HITEC. 1998 Fourth International. ; , s. 10-14
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Konferensbidrag (refereegranskat)abstract
- A parametric study of the etching characteristics of 6H p+ and n+ SiC and thin film SiC0.5N0.5 in Inductively Coupled Plasma NF3/O2 and NF 3/Ar discharges has been performed. The etch rates in both chemistries increase monotonically with NF3 percentage and rf chuck power. The etch rates go through a maximum with increasing ICP source power, which is explained by a trade-off between the increasing ion flux and the decreasing ion energy. The anisotropy of the etched features is also a function of ion flux, ion energy and atomic fluorine neutral concentration. Indium-tin-oxide (ITO) masks display relatively good etch selectivity over SiC (maximum of 70:1), while photoresist etches more rapidly than SiC. The surface roughness of SiC is essentially independent of plasma composition for NF3/O2 discharges, while extensive surface degradation occurs for SiCN under high NF3:O2 conditions
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| 7. |
- 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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| 8. |
- Zetterling, Carl-Mikael, et al.
(författare)
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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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| 9. |
- Zetterling, Carl-Mikael, et al.
(författare)
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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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