Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Semiconductor Substrates
O 17.6: Vortrag
Montag, 31. März 2014, 17:15–17:30, PHY C 213
Initial-stage oxidation products on Si(111)-(7x7) in AFM and STM — Jo Onoda1, •Martin Ondracek2, Ayhan Yurtsever3, Pavel Jelinek1,2, and Yoshiaki Sugimoto1 — 1Graduate School of Engineering, Osaka University, Suita, Osaka, Japan — 2Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic — 3The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan
Studying the defects that form on a silicon surface in the initial stages of oxidation is important from the technological point of view and resolving the existing controversies regarding the structure of these defects can also contribute to better understanding the experimental techniques that were used in the studies. We investigated structures that appear in the initial oxidation stage of the Si(111)-(7×7) surface using the combined techniques of non-contact atomic force microscopy (AFM) and scanning tunneling microscopy (STM). We identified the defects resulting from initial oxidation as the ins×1 and ins×2 structures (1 or 2 oxygen atoms in backbonds of Si adatom) and the secondary oxidation product as the ad-ins×3 structure (3 oxygen atoms in the backbonds and 1 on top). We excluded the presence of adsorbed O2 molecules on the surface. We used ab initio simulations with a diverse range of tip models to interpret the experimental data and to clarify the mechanisms that lead to the observed forces and tunneling currents.