Strain and composition in SiGe nanoscale islands studied by x-ray scattering
Strain and composition in SiGe nanoscale islands studied by x-ray scattering
复制标题
通过 X 射线散射研究 SiGe 纳米级岛的应变和成分
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
H. Wawra
中科院分区：
文献类型：
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作者：
T. Wiebach;M. Schmidbauer;M. Hanke;H. Raidt;R. Köhler;H. Wawra
对在Si（001）上生长的应变SiGe纳米级岛进行了高分辨X射线衍射。倒易空间图显示了广泛延伸的“蝴蝶”形岛反射和衬底反射周围的强漫散射。从这样的强度图的Ge含量和其分布内的岛屿进行评估。这是通过模拟各种岛屿模型的漫散射来完成的。岛的形状是从原子力和扫描电子显微镜已知的。唯一的自由参数是Ge分布，这里近似由垂直浓度分布。随着Ge含量在约三分之一的岛高处的突然增加，实现了与实验结果相当好的一致性。然后通过有限元计算给出岛中的应变分布，有限元计算是模拟算法的一部分。
High-resolution x-ray diffraction has been performed on strained SiGe nanoscale islands grown coherently on Si(001). Reciprocal space maps show a widely extended ``butterfly'-shaped island reflection and strong diffuse scattering around the substrate reflection. From such intensity maps the Ge content and its distribution inside the islands are evaluated. This is done by simulation of diffuse scattering for a variety of island models. The island shape is known from atomic force and scanning electron microscopy. The only free parameter was the Ge distribution, here approximated by a vertical concentration profile. With an abrupt increase of Ge content at about one third of the island height a rather good agreement with the experimental results is achieved. The strain distribution in the islands is then given by the finite element calculations, which are part of the simulation algorithm.