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O: Fachverband Oberflächenphysik

O 68: Semiconductor substrates: Epitaxy and growth

O 68.3: Vortrag

Donnerstag, 25. März 2010, 11:00–11:15, H42

Microscopic picture of hydrogen on the (MO)VPE-preparation of Si(100) — •Anja Dobrich, Henning Döscher, Sebastian Brückner, Peter Kleinschmidt, Oliver Supplie, Christian Höhn, and Thomas Hannappel — Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin, Germany

The preparation of Si(100) in the (MO)VPE environment usually involves hydrogen as carrier gas and as by-product from precursors. Hydrogen is suggested to have a crucial impact on the step structure of the silicon surface. To study the complete microscopic picture of the Si(100) surface we observed the (MO)VPE-preparation in situ with reflection anisotropy spectroscopy (RAS) and with a variety of surface-sensitive UHV-based techniques using a contamination-free (MO)VPE to UHV transfer system. Correlation between these results led to the conclusion that the surface is covered with hydrogen, in form of monohydrides and the surface is completely terminated with monohydrides. FTIR-spectroscopy in an attenuated total reflection (ATR) configuration served to perform surface-sensitive measurements of silicon-hydrogen bonds. This is in agreement with results from LEED and STM, which indicated that the surface unit cell consists of dimers. While our results were in agreement with the existence of H-Si-Si-H dimers, ATR spectroscopy did not reveal to what extent dangling bonds of the surface silicon atoms were saturated with hydrogen. Therefore we carried out tip-induced H-desorption by STM, which evidenced complete H-termination of the surface.