CHEMICAL-REACTIONS OF CHLORINE ON A VICINAL SI(100) SURFACE STUDIED BY ESDIAD

The reaction of Cl-2 on a vicinal Si(100) surface has been studied by ESDIAD. This type of surface possesses two types of sites: pairs of dangling bonds on Si-Si terrace dimers, and single dangling bonds on the 2-atom layer high steps. The reactivity of these two sites is compared. For low coverages the step dangling bonds are identified as the preferred Cl bonding site after 673 K-annealing. Upon higher temperature annealing and SiCl2(g) desorption, the terrace-site Cl species are depleted more rapidly than the step-site Cl species. Extensive isothermal etching under a continuous Cl-2 flux at 800 K is found to produce a disordered surface structure. Heating to 1123 K causes a reordering of the surface.