SiC HTCVD Simulation Modified by Sublimation Etching

Kito, Yasuo; Makino, Emi; Ikeda, Kei; Nagakubo, Masao; Onda, Shoichi

doi:10.4028/www.scientific.net/msf.527-529.107

Cited by 20 publications

(13 citation statements)

References 5 publications

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“…The surface-covering graphene sheet certainly obstructs Si sublimation away from the substrate surface [47,48]. Since perfect graphene sheets only have small six-member C rings, any Si atom has difficulty passing through the sheet.…”

Section: The Role Of Steps In Epitaxial Graphene Growthmentioning

confidence: 99%

The physics of epitaxial graphene on SiC(0001)

Kageshima

Hibino²,

Tanabe³

2012

J. Phys.: Condens. Matter

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Various physical properties of epitaxial graphene grown on SiC(0001) are studied. First, the electronic transport in epitaxial bilayer graphene on SiC(0001) and quasi-free-standing bilayer graphene on SiC(0001) is investigated. The dependences of the resistance and the polarity of the Hall resistance at zero gate voltage on the top-gate voltage show that the carrier types are electron and hole, respectively. The mobility evaluated at various carrier densities indicates that the quasi-free-standing bilayer graphene shows higher mobility than the epitaxial bilayer graphene when they are compared at the same carrier density. The difference in mobility is thought to come from the domain size of the graphene sheet formed. To clarify a guiding principle for controlling graphene quality, the mechanism of epitaxial graphene growth is also studied theoretically. It is found that a new graphene sheet grows from the interface between the old graphene sheets and the SiC substrate. Further studies on the energetics reveal the importance of the role of the step on the SiC surface. A first-principles calculation unequivocally shows that the C prefers to release from the step edge and to aggregate as graphene nuclei along the step edge rather than be left on the terrace. It is also shown that the edges of the existing graphene more preferentially absorb the isolated C atoms. For some annealing conditions, experiments can also provide graphene islands on SiC(0001) surfaces. The atomic structures are studied theoretically together with their growth mechanism. The proposed embedded island structures actually act as a graphene island electronically, and those with zigzag edges have a magnetoelectric effect. Finally, the thermoelectric properties of graphene are theoretically examined. The results indicate that reducing the carrier scattering suppresses the thermoelectric power and enhances the thermoelectric figure of merit. The fine control of the Fermi energy position is thought to be key for the practical use of graphene as a thermoelectric material, which could be achieved with epitaxial graphene. All of these results reveal that epitaxial graphene is physically interesting.

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Section: The Role Of Steps In Epitaxial Graphene Growthmentioning

confidence: 99%

The physics of epitaxial graphene on SiC(0001)

Kageshima

Hibino²,

Tanabe³

2012

J. Phys.: Condens. Matter

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“…The growth rate can be simplified in the formula of GR £ DC 0 /¤ when the partial pressure of the gas species is much higher than the equilibrium vapor pressure between solid SiC and the gas phase, where GR is the growth rate, D is the diffusion coefficient of the gas species, C 0 is the density of the gas species outside of the boundary layer and ¤ is the boundary layer thickness. 18) When no homogeneous nucleation of the precursors takes place in the gas phase, C 0 is proportional to the system pressure (P) and the product of DC 0 is unchanged by varying P under the constant mass flow rates, since D is inversely proportional to P. In this case, GR is inversely proportional to ¤. In the case of a general gas flow, ¤ over a flat plane is proportional to [®/(Uμ)] 1/2 , where U is the general gas flow speed out of the boundary layer, μ is the gas density and ® is the viscosity.…”

mentioning

confidence: 99%

Development of a 150 mm 4H-SiC epitaxial reactor with high-speed wafer rotation

Fujibayashi

Ito

et al. 2013

Appl. Phys. Express

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A new type of 150 mm vertical 4H-SiC epitaxial reactor with high-speed wafer rotation has been developed. Multiple resistance heaters ensure uniform radial temperature distribution throughout a 150-mm-diameter wafer. Enhancement of the growth rates is realized by high-speed wafer rotation under a relatively high system pressure, and growth rates of 40–50 µm/h are achieved on 4° off 4H-SiC substrates, maintaining a low defect density and a smooth surface without macrostep bunching. Excellent thickness and doping uniformities are simultaneously obtained for a 150-mm-diameter wafer at a high growth rate of 50 µm/h.

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“…The temperature of the gas-cracking zone and the walls should be slightly higher than that of the seed crystal, to ensure mass transport and condensation on the seed. The typical growth pressures and growth rates are 25-80 kPa and 0.3-1.5 mm/h, respectively [82][83][84].…”

Section: High-temperature Chemical Vapor Depositionmentioning

confidence: 99%