Hamburg 2001 – scientific programme

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O: Oberflächenphysik

O 23: Oxide und Isolatoren (I)

O 23.4: Talk

Tuesday, March 27, 2001, 17:00–17:15, M

Oxidation of CoGa(100) Surface — •Feng-Ming Pan, Christian Pflitsch, Rudolf David, Laurens Verheij, and René Franchy — Institut für Grenzflächenforschung und Vakuumphysik, Forschungszentrum Jülich, D-52425 Jülich, Germany

The preparation of ordered β-Ga₂O₃ on the CoGa(100) surface by exposing the surface to oxygen has been studied by thermal energy helium atom scattering (TEAS), low energy electron diffraction (LEED) and Auger electron spectroscopy (AES). Upon oxidation at 300 K followed by subsequent annealing at 700 K, the β-Ga₂O₃ film is not continuous. Around 15% of the surface remains uncovered by the oxide after this preparation method. A continuous and well ordered β-Ga₂O₃ film with a uniform thickness is obtained after oxidation above 600 K. When the oxygen partial pressure is larger than 2×10⁻⁷ mbar, well ordered β-Ga₂O₃ is produced for oxidation at 900 K, which is higher than the desorption temperature (850 K) of oxygen from the CoGa(100) surface. Increasing the oxidation temperature from 600 K to 900 K results in an increase of the helium reflectivity, and the diffraction peak width decreases, indicating that the average size of the oxide domains increases and, consequently, that the step density decreases with the oxidation temperature.