Observation of strain field fluctuation in SiGe-relaxed buffer layers and its influence on overgrown structures
Observation of strain field fluctuation in SiGe-relaxed buffer layers and its influence on overgrown structures
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DOI：
10.1016/j.mssp.2004.09.100
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发表时间：
2005-02
影响因子：
4.1
通讯作者：
K. Sawano;N. Usami;K. Arimoto;S. Koh;K. Nakagawa;Y. Shiraki
中科院分区：
文献类型：
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作者：
K. Sawano;N. Usami;K. Arimoto;S. Koh;K. Nakagawa;Y. Shiraki
利用空间分辨显微拉曼光谱研究了应变Si/应变弛豫SiGe缓冲层中的面内应变场分布。在应变Si和SiGe层中都观察到了类似于交叉线的应变分布，表明来自底层失配位错的应变场到达SiGe表面，引起应变Si层中的应变起伏。发现分布的波长强烈地依赖于SiGe厚度。波动的量对应于应变Si层固有的应变的13%。应变场调制了过生长层的局部生长速率，导致表面粗糙度的增加。应变波动，因此，应仔细考虑器件的应用。
We investigated in-plane strain field distribution in strained-Si/strain-relaxed SiGe buffer layers by spatially resolved micro-Raman spectroscopy. Crosshatch-like strain distribution was observed in both the strained-Si and SiGe layer, indicating that strain field coming from underlying misfit dislocations reaches the SiGe surface and causes the strain fluctuation in the strained-Si layer. The wavelength of the distribution was found to strongly depend on the SiGe thickness. The amount of the fluctuation corresponded to 13% of the strain that strained-Si layer inherently had. It was also found that the strain field modulated the local growth rate of overgrown layer and caused the enhancement of the surface roughness. The strain fluctuation, therefore, should be carefully taken into account for device applications.