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Silicon carbide is a semiconductor material with ideal properties for high temperature and high power applications. The epitaxial layer fabrication is usually performed using CVD under a hydrogen rich atmosphere and high temperature. At such conditions the surface of the growing layer is expected to be passivated by the abundantly present hydrogen. In this work, we use quantum chemical density functional theory (B3LYP and M06-2X) and transition state theory to study surface reactions related to the deposition of carbon on the (0001) surface of 4H−SiC. We show that it is unlikely for an adsorption to occur on a passivated site unless the hydrogen termination is removed. We propose that unterminated sites can be effectively created during the CVD by an abstraction process. We provide details of the adsorption process of active carbon species, namely CH3, CH4, C2H2 and C2H4 gases, and their subsequent surface reactions such as desorption, abstraction of neighboring surface hydrogens 2 and dimer formation. The reaction rates and sticking coefficients are provided for the temperature range of 298−2500 K. Finally, entire reaction paths from adsorptions to stable surface products are presented and discussed.

Articles you may be interested in 3 ] have been investigated as precursors for intentional carbon doping of (0001) GaN in chemical vapor deposition. The carbon precursors were studied by comparing the efficiency of carbon incorporation in GaN together with their influence on morphology and structural quality of carbon doped GaN. The unsaturated hydrocarbons C 2 H 4 and C 2 H 2 were found to be more suitable for carbon doping than the saturated ones, with higher carbon incorporation efficiency and a reduced effect on the quality of the GaN epitaxial layers. The results indicate that the C 2 H 2 molecule as a direct precursor, or formed by the gas phase chemistry, is a key species for carbon doping without degrading the GaN quality; however, the CH 3 species should be avoided in the carbon doping chemistry.