AVS 45th International Symposium
    Surface Science Division Thursday Sessions
       Session SS1-ThA

Paper SS1-ThA2
Direct Measurement of Adsorbed Si Dimer Dynamics on Si(001)

Thursday, November 5, 1998, 2:20 pm, Room 308

Session: Surface Diffusion
Presenter: J.M. Carpinelli, Sandia National Laboratories
Authors: J.M. Carpinelli, Sandia National Laboratories
B.S. Swartzentruber, Sandia National Laboratories
Correspondent: Click to Email
Silicon atom deposition onto a clean, well-ordered Si(001) crystal surface results in the formation of adsorbed dimers. This presentation details the use of atom-tracking scanning tunneling microscopy to determine the detailed energetics of such species in a variety of local environments at elevated temperatures (~ 100°C). Dimer diffusion along a buckled A-type step edge is found to be weakly asymmetric, indicating that the adsorbed dimer does not strongly perturb the underlying substrate bonding. A dimer adsorbed onto the middle of a terrace is attracted at only a single lattice site to a 2+1 defect in an adjacent diffusion channel, pinpointing the probable location of subsurface contamination responsible for defect formation. Additionally, a linear dependence between the activation barrier for diffusion and perpendicularly applied electric field magnitude is measured. These results provide valuable insight into the bonding and interaction of dimers with surface features prevalent during homoepitaxial growth. The quantitative measure of lattice-site specific energy parameters not only serves as input to realistic simulations, but also enables the validation and refinement of such calculations. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04- 94AL85000.