| Abstract: | We investgated the oxidation behaviors of Si1 - x Gex alloys(x=0.5%, 2%, 5%,15% and25%). Theoxi-dation of SiGe films with different compositions was carried out in O2 (dry) atmosphere at 800℃, 900℃ and 1000℃ respectively for various lengths of time. Thickness and property of nanoparticle and nanolayer in oxide films and germanium segregation in oxidation of SiGe alloys as obtained using high precision ellipsometer (HPE) show good agreement with Rutherford backscattering spectrometry (RBS), profile dektak instrument ( PDI ) and high - resolution scanning transmission electron microscopy (HR - STEM) observation. We found that the Ge content in the oxide layer increases with the Ge content in SiGe layers, Ge content in the oxide film decreases with the increase of oxidation temperature and time length. Rejection of Ge results in piling up of Ge at the interface between the growing SiO2 and the remaining SiGe which forms nanometer Ge - rich layer. And substantial interdiffusion of Si and Ge takes place in the remaining SiGe which leads to the complicated distribution of Ge segregation. Several new phenomenons were discovered, and the experimental results were discussed and simulated. For example, we discovered a nanometer cap layer over the oxide film after fast oxidation, in which there are a lot of Ge nanoparticles. The oxidation optimum of SiGe has been gotten to produce SiO2 film and Ge nanolayer. |
