SiGe合金氧化层中的纳米结构

我们在硅锗合金衬底上采用氧化等制膜方式生成零维和三维的纳米结构样品，用高精度椭偏仪(HPE)、卢瑟福背散射谱仪(RBS)和高分辨率扫描透射电子显微镜(HR-STEM)测量样品的纳米结构。并采用美国威思康新州立大学开发的Rump模拟软件对卢瑟福背散射谱(RBS)中的CHANNEL谱和RANDOM谱分别进行精细结构模拟。计算且测量出纳米氧化层与锗的纳米薄膜结构分布，并且反馈控制加工过程。优化硅锗半导体材料纳米结构样品的加工条件。我们在硅锗合金的氧化层表面中首次发现纳米锗量子点和量子层结构，我们首次提出的生成硅锗纳米结构的优化加工条件的氧化时间和氧化温度的匹配公式和理论模型与实验结果拟合得很好。

MECHANISM OF NANOSTRUCTURE IN OXIDATION OF Si1-xGex AL-LOYS

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.