Oxidation-enhanced condensation of Ge atoms on SiGe alloy layer studied by real-time photoelectron spectroscopy

Ogawa, Shuichi*; Hozumi, Hideaki*; Yoshigoe, Akitaka ; Ishizuka, Shinji*; Kaga, Toshiteru*; Teraoka, Yuden; Takakuwa, Yuji*

The oxidation-enhanced Ge atoms condensation kinetics on an SiGe alloy layer has been investigated by the real-time photoemission spectroscopy using the synchrotron radiation. The SiGe alloy layer was formed with a thermal evaporation method on a p-type Si(001) surface, and this alloy layer was oxidized at Langmuir-type adsorption. During oxidation at 773 KC, it is found that the Ge atoms are not oxidized, only SiO film is formed on the SiGe alloy layer. Furthermore, the desorption of GeO molecules does not occur during the oxidation of alloy layer. On the other hand, not only Si atoms but also Ge atoms are oxidized at room temperature. This difference can be explained using the unified oxidation model mediated by the point defect generation, namely it is suggested that a lot of vacancies are generated during oxidation of the SiGe alloy layer at 773K and Ge atoms diffuse through these vacancies.