Misfit dislocation dissociation and Lomer formation in low mismatch SiGe/Si heterostructures
Misfit dislocation dissociation and Lomer formation in low mismatch SiGe/Si heterostructures
复制标题
低失配 SiGe/Si 异质结构中的错配位错解离和 Lomer 形成
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
P. McIntyre
中科院分区：
文献类型：
--
作者：
A. Marshall;D. B. Aubertine;W. Nix;P. McIntyre
用电子显微镜观察到SiGe/Si多层膜界面有60°失配位错的离解，向衬底延伸5.0-7.5 nm。弹性理论分析表明，与体硅中60°混合位错一样，这种离解是单个60°错配位错的平衡组态，压缩应变多层膜主要起到相对于自由面定位部分位错和层错的作用。我们观察到退火后未解离的60°位错和Lmer刃位错，认为这是位错在界面上攀移的结果。由于位错在攀爬过程中移出滑移面，它们不可能保持解离状态。在850℃以上的温度和具有较高初始位错密度的样品中，观察到这些低失配层的显著攀移和Lmer位错形成，例如在较厚的原始样品中发现的。在退火过程中形成的位错构型与报道的在高失配薄膜生长过程中形成的位错构型不同：Lmer位错倾向于分段，各段之间由完美的60°位错连接。
Using transmission electron microscopy we observe the dissociation of 60° misfit dislocations at the interface of SiGe/Si multilayers, extending into the substrate for distances of 5.0–7.5 nm. Analysis using elasticity theory shows that this dissociationis the equilibrium configuration for individual 60° misfit dislocations, as it is for 60° mixed dislocations in bulk Si, and that the compressively strained multilayer film serves mainly to position the partial dislocations and stacking fault with respect to the free surface. We observe both undissociated 60° and Lomer edge dislocations after annealing, and conclude that these result from dislocation climb in the interface. Since the dislocations move off their slip plane during climb, they cannot remain dissociated. Significant climb and Lomer dislocation formation for these low misfit layers is observed at temperatures above 850 °C and for samples with a high initial dislocation density, such as found in thicker as-grown samples. The dislocation configuration formed during annealing is distinct from that reported to form during growth of higher mismatch films: the Lomer dislocations tend to be segmented, with the segments connected by perfect 60° dislocations.