Oxidation of 4H-SiC covered with a SmSix surface alloy |
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| Authors: | M Kildemo U Grossner BG Svensson |
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| Institution: | a Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway
b Department of Physics and Center for Materials Science and Nanotechnology, University of Oslo, N-0371 Oslo, Norway |
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| Abstract: | Oxidation of Sm/4H-SiC is studied by X-ray photoemission spectroscopy (XPS) and low energy electron diffraction (LEED). In particular, we report kinetic information from the oxidation of a SmSix (1 × 1) surface alloy formed on (0 0 0 1) 4H-SiC. During the initial oxidation of the SmSix alloy, a (2 × 2)-LEED pattern is observed. Furthermore, the Sm 2+ valency observed from the clean SmSix surface alloy, which is related to surface samarium atoms, disappear at 15 L oxygen exposure. The oxygen atom is consequently deduced to be located at bridge or hollow sites involving one Sm atom. The initial oxidation result in an oxygen deficit SmSiOx interface oxide, probably as a consequence of the high oxidation temperatures in this work (900-1050 °C). We report that in a prolonged oxidation (longer than 10 kL) a SiO2 layer forms on top of the samarium silicon oxide interface layer. |
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| Keywords: | Soft X-ray photoelectron spectroscopy Catalysis Surface electronic phenomena Silicon Carbon Samarium Rare earth oxide Alloys Semiconductor-insulator interfaces |
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