ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The origin of the polytypes of SiC has been investigated from the viewpoint of surfacereactions by the density functional theory (DFT) within the Projector Augmented Wave-GeneralizedGradient Approximation. Three radicals were considered here as the major species in the crystalgrowth process: Si, Si2C and SiC2. We supposed that these radicals contribute to the crystal growthdirectly through the adsorption on the 4H-SiC (000-1) C-face surface. The DFT calculations showedthat the Si2C, which relatively has a similar structure with the SiC crystal, had no activation barrier tobe adsorbed chemically to the 4H-SiC C-face surface. On the other hand, SiC2 with Si showed anactivation barrier of 0.79eV to form the 4H-SiC crystal. In order to investigate the arrangements todecide polytypism in SiC, we compared the adsorption energies between the different sites, whichcorrespond to the 4H-SiC crystal and a disordered arrangement. The activation energies had almost nodifference. Our calculations indicated that these radicals do not contribute to the origin of thepolytypes of SiC
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.527-529.235.pdf
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