SiGe合金氧化层中的纳米结构

Nanoparticle and Nanolayer in Oxide Film and Substantial Ge Segregation

在硅锗合金衬底上采用氧化等制膜方式生成零维和二维的纳米结构样品 ,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 ,测量并计算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 .在硅锗合金的氧化层表面中首次发现纳米锗量子点组成的纳米盖帽薄膜 ( 2nm) 。

Author investgated the oxidation behaviors of Si 1-x Gex alloys with a 0.5%, 2%, 5%,15% and 25% Ge content. The oxidation of SiGe films with different compositions is carried out in dry oxygen gas at 800℃,900℃ and 1000℃ for various length 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 observed that the Ge content in the oxide layer increased with the Ge content in SiGe layers, Ge content in the oxide film decreased with the increase of oxidation temperature and with the increase of 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. The oxidation optimum of SiGe has been obtained.