| 1. |
- Booker, Ian Don, et al.
(författare)
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Comparison of post-growth carrier lifetime improvement methods for 4H-SiC epilayers
- 2012
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Ingår i: Silicon Carbide And Related Materials 2011, Pts 1 And 2. - : Trans Tech Publications Inc.. - 9783037854198 ; , s. 285-288, s. 285-288
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Konferensbidrag (refereegranskat)abstract
- We compare two methods for post-growth improvement of bulk carrier lifetime in 4H-SiC: dry oxidations and implantations with either 12C or 14N, followed by high temperature anneals in Ar atmosphere. Application of these techniques to samples cut from the same wafer/epilayer yields 2- to 11-fold lifetime increases, with the implantation/annealing technique shown to give greater maximum lifetimes. The maximum lifetimes reached are ∼5 μs after 12C implantation at 600 °C and annealing in Ar for 180 minutes at 1500 °C. At higher annealing temperatures the lifetimes decreases, a result which differs from reports in the literature.
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| 2. |
- Danielsson, Örjan, et al.
(författare)
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Simulation of Gas-Phase Chemistry for Selected Carbon Precursors in Epitaxial Growth of SiC
- 2013
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Ingår i: Materials Science Forum. - : Trans Tech Publications. - 0255-5476 .- 1662-9752. ; 740-742, s. 213-216
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Tidskriftsartikel (refereegranskat)abstract
- Numerical simulations are one way to obtain a better and more detailed understanding of the chemical vapor deposition process of silicon carbide. Although several attempts have been made in this area during the past ten years, there is still no general model valid for any range of process parameters and choice of precursors, that can be used to control the growth process, and to optimize growth equipment design. In this paper a first step towards such a model is taken. Here, mainly the hydrocarbon chemistry is studied by a detailed gas-phase reaction model, and comparison is made between C3H8 and CH4 as carbon precursor. The results indicate that experimental differences, which previous models have been unable to predict, may be explained by the new model.
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| 3. |
- Danielsson, Örjan, et al.
(författare)
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Simulations of SiC CVD - Perspectives on the need for surface reaction model improvements
- 2014
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2013, PTS 1 AND 2. - : Trans Tech Publications. ; , s. 218-221
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Konferensbidrag (refereegranskat)abstract
- Simulations of SiC chemical vapor deposition is an excellent tool for understanding, improving and optimizing this complex process. However, models used up to date have often been validated for one particular set of process parameters, often in the silicon limited growth regime, in one particular growth equipment. With chlorinated precursors optimal growth condition is often found to take place at the border between carbon limited and silicon limited regimes. At those conditions the previous models fail to predict deposition rates properly. In this study we argue that molecules like C2H2, C2H4 and CH4, actually might react with the surface with much higher rates than suggested before. Comparisons are made between the previous model and our new model, as well as experiments. It is shown that higher reactivities of the hydrocarbon molecules will improve simulation results as compared to experimental findings, and help to better explain some of the trends for varying C/Si ratios.
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| 4. |
- Gueorguiev Ivanov, Ivan, et al.
(författare)
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Optical properties of the niobium centre in 4H, 6H, and 15R SiC
- 2013
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2012. - : Trans Tech Publications. ; , s. 405-408
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Konferensbidrag (refereegranskat)abstract
- A set of lines in the photoluminescence spectra of 4H-, 6H-, and 15R-SiC in the near-infrared are attributed to Nb-related defects on the ground of doping experiments conducted with 4H-SiC. A model based on a an exciton bound at the Nb-centre in an asymmetric split vacancy configuration at a hexagonal site is proposed, which explains the structure of the luminescence spectrum and the observed Zeeman splitting of the lines.
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| 5. |
- Henry, Anne, et al.
(författare)
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Chloride based CVD of 3C-SiC on (0001) α-SiC substrates
- 2011
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Ingår i: <em>Materials Science Forum Vols. 679-680 (2011) pp 75-78</em>. - : Trans Tech Publications Inc.. ; , s. 75-78
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Konferensbidrag (refereegranskat)abstract
- A chloride-based chemical-vapor-deposition (CVD) process has been successfully used to grow very high quality 3C-SiC epitaxial layers on on-axis α-SiC substrates. An accurate process parameters study was performed testing the effect of temperature, surface preparation, precursor ratios, nitrogen addition, and substrate polytype and polarity. The 3C layers deposited showed to be largely single-domain material of very high purity and of excellent electrical characteristics. A growth rate of up to 10 μm/h and a low background doping enable deposition of epitaxial layers suitable for MOSFET devices.
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| 6. |
- Henry, Anne, et al.
(författare)
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Concentrated chloride-based epitaxial growth of 4H-SiC
- 2010
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Ingår i: Materials Science Forum, Vols. 645-648. - : Transtec Publications; 1999. ; , s. 95-98
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Konferensbidrag (refereegranskat)abstract
- A chloride-based CVD process has been studied in concentrated growth conditions. A systematic study of different carrier flows and pressures has been done in order to get good quality epilayers on 8 degrees off and on-axis substrates while using very low carrier flows. Hydrogen chloride (HCl) was added to the standard gas mixture to keep a high growth rate and to get homo-polytypic growth on on-axis substrates. The carrier flow was reduced down to one order of magnitude less than under typical growth condition. By lowering the process pressure it was possible to reduce precursor depletion along the susceptor which improved the thickness uniformity to below 2% variation (sigma/mean) over a 2 diameter wafer.
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| 7. |
- Henry, Anne, et al.
(författare)
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Epitaxial growth on on-axis substrates
- 2012
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Ingår i: Silicon Carbide Epitaxy. - Kerala, India : Research Signpost. - 9788130805009 ; , s. 97-119
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Bokkapitel (refereegranskat)abstract
- SiC epitaxial growth using the Chemical Vapour Deposition (CVD) technique on nominally on-axis substrate is presented. Both standard and chloride-based chemistry have been used with the aim to obtain high quality layers suitable for device fabrication. Both homoepitaxy (4H on 4H) and heteroepitaxy (3C on hexag onal substrate) are addressed.
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| 8. |
- Henry, Anne, et al.
(författare)
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SiC epitaxy growth using chloride-based CVD
- 2012
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Ingår i: Physica. B, Condensed matter. - : Elsevier. - 0921-4526 .- 1873-2135. ; 407:10, s. 1467-1471
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Tidskriftsartikel (refereegranskat)abstract
- The growth of thick epitaxial SiC layers needed for high-voltage, high-power devices is investigated with the chloride-based chemical vapor deposition. High growth rates exceeding 100 mu m/h can be obtained, however to obtain device quality epilayers adjustments of the process parameters should be carried out appropriately for the chemistry used. Two different chemistry approaches are compared: addition of hydrogen chloride to the standard precursors or using methyltrichlorosilane, a molecule that contains silicon, carbon and chlorine. Optical and electrical techniques are used to characterize the layers.
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| 9. |
- Ivanov, Ivan Gueorguiev, et al.
(författare)
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High-Resolution Raman and Luminescence Spectroscopy of Isotope-Pure (SiC)-Si-28-C-12, Natural and C-13 - Enriched 4H-SIC
- 2014
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Ingår i: Silicon Carbide and Related Materials 2013, PTS 1 AND 2. - : Trans Tech Publications Inc.. ; , s. 471-474
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Konferensbidrag (refereegranskat)abstract
- The optical properties of isotope-pure (SiC)-Si-28-C-12, natural SiC and enriched with C-13 isotope samples of the 4H polytype are studied by means of Raman and photoluminescence spectroscopies. The phonon energies of the Raman active phonons at the Gamma point and the phonons at the M point of the Brillouin zone are experimentally determined. The excitonic bandgaps of the samples are accurately derived using tunable laser excitation and the phonon energies obtained from the photoluminescence spectra. Qualitative comparison with previously reported results on isotope-controlled Si is presented.
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| 10. |
- Janzén, Erik, et al.
(författare)
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Silicon Carbide - The Power Device for the Future
- 2012
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Ingår i: 2012 18TH INTERNATIONAL WORKSHOP ON THERMAL INVESTIGATIONS OF ICS AND SYSTEMS (THERMINIC). - : IEEE. ; , s. 119-124
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Konferensbidrag (refereegranskat)abstract
- Silicon Carbide (SiC) is a wide bandgap semiconductor with highly appreciated properties making it ideal for high power, high frequency, and high temperature applications. One of these properties is the high thermal conductivity (lambda) which is mentioned in almost every single publication, yet very few measurements of lambda on SiC have been made and essentially no knowledge has been accumulated on the limiting factors on lambda or on what role lambda plays in a finished device. Improvement of lambda may be achieved if the material is isotope enriched i.e. the SiC is dominatingly (SiC)-Si-28-C-12. In this paper we will highlight the properties of SiC as a power device material with specific emphasis on lambda. The results from (SiC)-Si-28-C-12 show that the layers are very low doped and have an isotope purity of 99% or better.
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