AVS 49th International Symposium
    Surface Science Thursday Sessions
       Session SS+EL-ThA

Paper SS+EL-ThA4
An Atom-Resolved Study of Vacancy Dynamics and Surface Roughening on Bromine-Etched Si(100) Surfaces

Thursday, November 7, 2002, 3:00 pm, Room C-112C

Session: Growth & Etching on Semiconductor Surfaces
Presenter: C.F. Herrmann, University of North Carolina, Chapel Hill
Authors: C.F. Herrmann, University of North Carolina, Chapel Hill
J.J. Boland, University of North Carolina, Chapel Hill
Correspondent: Click to Email
Halogen etching of Si(100) surfaces has long been considered to involve the selective removal of atoms from an essentially static surface. However, our high temperature scanning tunneling microscopy (STM) study reveals that halogen-covered surfaces are highly unstable. This instability stems from the inherent steric repulsions between halogen adatoms on the surface. At high temperatures, repulsive interactions are relieved by vacancy formation, diffusion and surface roughening, each of which is directly observed in real-time by STM. Together, these dynamical processes result in surface features identical to those found after high temperature etching. These results demonstrate that diffusion and roughening must be considered in any model of halogen etching. Moreover, steric repulsions and the instability they create place fundamental limits on the ability to achieve atomically smooth morphologies using halogen etching.