AVS 45th International Symposium
    Surface Science Division Thursday Sessions
       Session SS-ThP

Paper SS-ThP15
Barrier-Height Imaging of Defects on the Si(001) 2x1 Surface

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Surface Science Division Poster Session
Presenter: S. Kurokawa, Kyoto University, Japan
Authors: S. Kurokawa, Kyoto University, Japan
A. Sakai, Kyoto University, Japan
Correspondent: Click to Email
The C-type defect on the Si(001) 2x1 surface is known to be an active site in Fermi level pinning and also in the initial oxidation of Si(001). In spite of its practical importance, the atomic structure of this defect has not completely understood yet. Controversies also exist on the tunneling barrier height at the C defect. Hamers and Köhler@footnote 1@ found that the barrier height decreases around the defect but increases just above the defect site. On the other hand, Ukraintsev et al.@footnote 2@ reported no such changes in the barrier height at and around the C defect. We have performed the STM barrier-height imaging on clean and oxygen-adsorbed Si(001) 2x1 surfaces and investigated the barrier height at various surface defects. We find that the apparent barrier height at the C defect closely follows the STM corrugation profile: the barrier height increases at the defect site under positive sample bias, but shows no depression around the defect. Our finding is consistent with the relation between barrier-height and STM images but not in agreement with Hamers and Köhler.@footnote 1@ Upon exposure to 1L of oxygen, preliminary barrier-height measurements show that the apparent barrier height at the C defect site appears to be reduced. The effects of oxygen adsorption on other surface defects will also be presented. @FootnoteText@ @footnote 1@R. J. Hamers and U. K. Köhler, J.Vac.Sci.Technol. A7, 2854 (1989). @footnote 2@V. A. Ukraintsev, Z. Dohnalek, and J. T. Yates. Jr., Surf. Sci. 388, 132 (1997).