Abstract

The kinetics of Si monomers, at submonolayer coverage, are measured using STM. Si monomers are observed in empty-state images acquired between room temperature and 115 C. The monomers become trapped at the ends of rebonded-SB type dimer rows, while substrate defects and SA type steps act as reflection barriers. At elevated temperatures, monomers thermally escape from the traps and diffuse one-dimensionally along the substrate dimer row until they find another unoccupied trap or return to their original trap. From the rate at which the monomers escape from the traps, the binding activation barrier at isolated traps is estimated to be ~ 1.0 eV. A slightly lower barrier exists for monomers to hop between traps located at the ends of neighboring dimer rows -- a process facilitating diffusion along segments of the SB type steps.

© 1997 Optical Society of America