Spherical aberration corrected STEM studies of Ge nanodots grown on Si(0 0 1) surfaces with an ultrathin SiO2 coverage
Spherical aberration corrected STEM studies of Ge nanodots grown on Si(0 0 1) surfaces with an ultrathin SiO2 coverage
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DOI：
10.1016/j.apsusc.2008.01.033
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发表时间：
2008-09
影响因子：
6.7
通讯作者：
N. Tanaka;Sung-pyo Cho;A. Shklyaev;J. Yamasaki;E. Okunishi;M. Ichikawa
中科院分区：
文献类型：
--
作者：
N. Tanaka;Sung-pyo Cho;A. Shklyaev;J. Yamasaki;E. Okunishi;M. Ichikawa
在轻微氧化的硅表面上形成尺寸约为7nm、密度为2×1012cm−2的锗（Ge）纳米点。球差校正扫描透射电子显微镜（Cs校正STEM）清楚地揭示了纳米点、氧化物层和硅基底之间的尺寸、纵横比和界面结构。特别是，在此类样品中首次发现了 SiO2 层下方的富 Ge 薄层。通过 EELS 和 EDX 在 Cs 校正的 STEM 中分析通过界面的元素分布。高分辨率 Cs 校正环形暗场 (ADF)-STEM 图像清楚地显示了富 Ge 晶体层的存在及其与 Z 对比度图像中氧化物层的几何形状。提出了Ge纳米点在轻微氧化的硅表面上的新生长模型。
Germanium (Ge) nanodots of about 7nm size and 2×1012cm−2density were formed on slightly oxidized silicon surfaces. The spherical aberration corrected scanning transmission electron microscopy (Cs-corrected STEM) revealed clearly the size, aspect ratio and interface structures among the nanodots, oxide layers and silicon substrates. In particular, a Ge-rich thin layer underneath SiO2layers was found for the first time in these kinds of samples. The elemental distribution through the interface was analyzed by EELS and EDX in the Cs-corrected STEM. The high-resolution Cs-corrected annular dark field (ADF)-STEM image shows clearly the existence of a Ge-rich crystalline layer and its geometry against the oxide layer from the Z-contrast image. A new growth model of the Ge nanodots on slightly oxidized silicon surfaces was proposed.