Abstract In a previous study, we reported on a (110)-oriented strained Si pMOSFET with an effective hole mobility as high as 480 cm2/Vs. To impose the lattice strain on the Si channel layer, strain-relaxed SiGe buffer layer is utilized. Defect formation is requisite for strain relaxation in SiGe layer, and at the same time, has the adverse effects for electrical properties of the strained Si film. Therefore, it is necessary to control the formation of the crystalline defects. The aim of this study is to investigate the evolution of the crystalline morphology during the growth of SiGe layers by solid source molecular beam epitaxy, which is utilized to optimize the structural parameters of the strain-relaxed SiGe buffer layers. It is revealed in this study that the lattice strain in SiGe formed on Si(110) begin to relax at a lower film thickness than in the case of SiGe on Si(001). Orientation dependences of surface morphology and degree of strain relaxation are found to be dependent on Ge composition. The development process of the growth twin is also discussed. It is shown that the growth twin generation is effectively suppressed by the composition grading technique.

中文翻译：

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固体源分子束外延在 Si(110) 上生长 SiGe 过程中的应变弛豫过程和晶体形态演变

摘要 在之前的研究中，我们报道了一种 (110) 取向的应变 Si pMOSFET，其有效空穴迁移率高达 480 cm2/Vs。为了在 Si 沟道层上施加晶格应变，使用了应变松弛的 SiGe 缓冲层。缺陷的形成是SiGe层应变弛豫的必要条件，同时对应变Si薄膜的电学性能也有不利影响。因此，有必要控制结晶缺陷的形成。本研究的目的是研究通过固体源分子束外延生长 SiGe 层过程中晶体形态的演变，用于优化应变松弛 SiGe 缓冲层的结构参数。本研究表明，与在 Si(001) 上形成的 SiGe 相比，在 Si(110) 上形成的 SiGe 中的晶格应变开始松弛。发现表面形态和应变松弛程度的取向依赖于Ge成分。还讨论了生长双胞胎的发展过程。结果表明，成分分级技术有效抑制了生长双胞胎的产生。