DISSOCIATIVE ADSORPTION OF SI2H6 ON SILICON AT HYPERTHERMAL ENERGIES - THE INFLUENCE OF SURFACE-STRUCTURE

The reactions of Si2H6 With the (100) and (111) surfaces of silicon have been investigated employing supersonic molecular beam scattering techniques. Incident translational energy has been found to influence strongly the probability of dissociative adsorption (S(R)) on both surfaces. The reaction on the Si(111) surface is distinct from that observed on Si(100) concerning the dependence of S(R) on the substrate temperature and the incident angle. In particular, the reaction on the (111) surface shows sensitivity to the surface phase transformation (7 x 7) --> (1 x 1) that occurs above 825-degrees-C. Both the dangling bond density and the effective corrugation of the surface are important in determining the reaction probability.