CARBON-ATOMS ON THE (2X1) RECONSTRUCTED SI(100) SURFACE

Binding energies and high energy binding sites were calculated for carbon atoms deposited on a (2 X 1) dimerized Si(100) surface. The location of the energetically most favorable binding site was found to be near the top position of a second layer Si atom with a binding energy of -3.36 eV. Also calculated were excess energies for the substitution of C (replacing Si atoms) in the exposed surface region. For the substitution of a carbon atom in surface layers 1 through 4 calculations produced progressively increasing excess energies from the exposed surface to the interior. This indicates that the diffusion of a substituting C atom from the top layer to the interior via a site exchange mechanism is energetically unfavorable.