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

Paper SS+EL-ThA5
Dynamics of Si(100)-(2x1) Surface Modification with Cl

Thursday, November 7, 2002, 3:20 pm, Room C-112C

Session: Growth & Etching on Semiconductor Surfaces
Presenter: G. Xu, University of Illinois at Urbana-Champaign
Authors: G. Xu, University of Illinois at Urbana-Champaign
E. Graugnard, University of Illinois at Urbana-Champaign
V. Petrova, University of Illinois at Urbana-Champaign
K.S. Nakayama, University of Illinois at Urbana-Champaign
J.H. Weaver, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
The etching dynamics of Cl-Si(100)-(2x1) at elevated temperature have been studied with variable temperature scanning tunneling microscopy. Clean samples were exposed to Cl@sub 2@ at room temperature to near saturation and then heated to 700 K for over 20 hours. By scanning the same area of the sample, we observed pit creation, diffusion, incorporation and annihilation. Pit annihilation has not been reported previously under conditions of steady state etching and surface saturation. We also observed regrowth islands creation, growth and decay. Surface reactions at 700 K produced single Si adatoms, which were bonded to Cl-free Si dimers. Single Si adatoms diffused through these Cl-free Si dimer sites, but adatom diffusion was restricted by the high Cl concentration. The adatoms could form regrowth dimers when they met or they could be accommodated at the ends of regrowth structures. The adatoms could also be released from the regrowth dimer rows with the assistance of bare dimers. We have also observed (3x2) and (5x2) surface structures and, for the first time, the phase transition between (3x2) and (5x2) structures and dimer vacancy lines.