Strain-relaxation mechanisms of SiGe layers formed by two-step growth on Si(0 0 1) substrates
Strain-relaxation mechanisms of SiGe layers formed by two-step growth on Si(0 0 1) substrates
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Si(0 0 1) 衬底上两步生长形成的 SiGe 层的应变弛豫机制
DOI：
10.1016/j.apsusc.2003.08.072
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Y. Yasuda
中科院分区：
文献类型：
--
作者：
Tomohiro Egawa;A. Sakai;Taishi Yamamoto;N. Taoka;O. Nakatsuka;S. Zaima;Y. Yasuda
我们研究了用两步应变弛豫法生长的Si（001）衬底上SiGe层的应变弛豫行为与位错结构之间的关系。通过平面透射电镜（TEM）观察，可以在SiGe/Si界面处观察到三种位错结构，反映了60°位错在SiGe层中的传播过程。平面透射电镜观察到应变松弛SiGe层中的螺纹位错与原子力显微镜观察到的表面凹坑形貌相对应。在两步生长后的样品中，通过x射线衍射测量的应变松弛程度大于通过TEM图像测量的SiGe/Si界面处的位错分离和60°位错的Burgers矢量[110]边缘分量估计的应变松弛程度。这表明除了60°位错的Burgers矢量[110]边缘分量外，其他因素也在SiGe缓冲层中沿[110]方向的应变松弛中起作用。
We have investigated the relationship between strain-relaxation behaviors and dislocation structures in SiGe layers on Si(001) substrates grown by the two-step stain-relaxation procedure. From the plan-view transmission electron microscopy (TEM) observation, three kinds of dislocation structures at the SiGe/Si interface can be observed, reflecting the propagation process of 60° dislocations in the SiGe layer. Threading dislocations in the strain-relaxed SiGe layer observed in the plan-view TEM image show the correspondence to pit morphologies formed on the surface detected by atomic force microscopy. In samples after the two-step growth, the degree of strain-relaxation measured by X-ray diffraction is found to be larger than that estimated from dislocation separations at the SiGe/Si interface measured from the TEM images and the [110] edge component of Burgers vector of the 60° dislocation. This indicates that additional factors other than the [110] edge component of Burgers vector of the 60° dislocation also play a role in relaxing the strain along the [110] direction in the SiGe buffer layer.