Ab initio investigation of C incorporation mechanisms on Si(001)

Ab initio calculations were performed to investigate adsorption and diffusi on of C on the Si(001) surface at different surface and subsurface sites. I ncorporation mechanisms of both substitutional and interstitial C during fi lm deposition and growth were proposed. A surface diffusion process resulti ng in interstitial C incorporation was identified and the calculated energy barrier of similar to 1.0 eV is consistent with the experimental value of 0.94 +/- 0.04 eV. The results support experimental observations of several groups: higher growth rates and lower temperatures favor the substitutional C incorporation. (C) 2000 American Institute of Physics. [S0003-6951(00)03 807-9].