Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 24: Postersitzung (Epitaxie und Wachstum, Oxide und Isolatoren, Elektronische Struktur, Oberfl
ächenreaktionen, Adsorption an Oberfl
ächen, Organische Dünnschichten)
O 24.24: Poster
Mittwoch, 26. März 2003, 14:30–17:30, P1
Investigations of SrO and BaO on the Si(001) surface — •J. Zachariae1, B. Pahl1, A. Kroeck2, H. Pfnür1, and K. Hofmann2 — 1Institut für Festkörperphysik, Universität Hannover, Appelstr. 2, 30167 Hannover — 2Institut für Halbleiterbauelemente und Werkstoffe, Universität Hannover, Appelstr. 11A, 30167 Hannover
The main interest of the investigation of the alkaline earth oxides BaO and SrO on the Si(001) surface is the generation of an epitaxial lattice matched mixed oxide layer with a high dielectric constant (єr≈30) compared to the classical gate oxide Si2O (єr=3,9). So far Amorphous SrO, BaO and Ba1−xSrxO layers were grown on Si(001) in UHV under variable conditions by direct evaporation of the oxides or by oxidizing of metallic layers. If the layers were grown by direct evaporation of the oxides in a low ambiance oxygen pressure, the layers showed a remarkably high non stoichiometric oxygen fraction. With XPS the stoichiometry and the oxidation of the substrate were checked, whereas EELS and UPS were used to determine the band structure. LEED was used to characterize epitaxial layers. Determination of the roughness by means of AFM and measurements of film thickness and with a spectral ellipsometer were performed under ambient conditions. Also the degeneration of the oxide layers under ambient conditions on long time scales were observed with the spectral ellipsometer. The appearance of tunneling current through the oxide layers was controlled by conductive-AFM.