CLUSTER MODEL STUDY OF THE CHEMISORPTION OF ATOMIC CARBON ON SI(100) SURFACES

Structural parameters for chemisorption of atomic carbon above a Si(10 0) surface have been obtained through a Si35H32 cluster model and a MI NDO/3 hamiltonian. The most stable position has been found to be the b ridge one when considering the unrelaxed surface. The stability increa ses about 14 kcal/mol when relaxation of the surface is allowed. Furth er research has been carried out using a reduced cluster model (Si9H12 ) at the ab initio Hartree-Fock level of calculation. Results confirm the increase of stability of the relaxed system. At this level, the bi nding energy is 90 kcal/mol for the unrelaxed surface and the stabiliz ation when the surface is relaxed is of about 20% with respect to the non-relaxed surface.