Surface mobility difference between Si and Ge and its effect on growth of SiGe alloy films and islands.
Surface mobility difference between Si and Ge and its effect on growth of SiGe alloy films and islands.
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DOI：
10.1103/physrevlett.96.016103
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发表时间：
2006-01
影响因子：
8.6
通讯作者：
Li Huang;Feng Liu;G. Lu;X. Gong
中科院分区：
文献类型：
--
作者：
Li Huang;Feng Liu;G. Lu;X. Gong
基于表面扩散势垒的第一性原理计算，我们发现在300 ~ 900 K的温度范围内，Ge（001）压缩表面的扩散率是Si的10(2)~ 10(3)倍，而在拉伸表面，两者的扩散率是相当的。因此，压缩SiGe薄膜的生长与拉伸薄膜的生长有很大的不同。与在Si上的Ge润湿层相比，Si和Ge在应变Ge岛屿上的扩散差异也大大增强（001），这解释了实验观察到的Si在润湿层中相对于在岛屿中富集。
Based on first-principles calculations of surface diffusion barriers, we show that on a compressive Ge(001) surface the diffusivity of Ge is 10(2)-10(3) times higher than that of Si in the temperature range of 300 to 900 K, while on a tensile surface, the two diffusivities are comparable. Consequently, the growth of a compressive SiGe film is rather different from that of a tensile film. The diffusion disparity between Si and Ge is also greatly enhanced on the strained Ge islands compared to that on the Ge wetting layer on Si(001), explaining the experimental observation of Si enrichment in the wetting layer relative to that in the islands.