标题： 非均匀低温外延断裂在GeSi量子点硅过度生长中的表现 显示英文标题

标题： Inhomogeneous low temperature epitaxial breakdown during Si overgrowth of GeSi quantum dots

摘要： 低温外延断裂的不均匀应变硅盖层被研究。 通过在共格应变的GeSi量子点表面生长硅薄膜，我们区分了表面粗糙度、应变和生长取向对外延断裂机制的影响。 使用原子力显微镜和高分辨率横向截面透射电子显微镜，我们发现尽管局部晶格应变高达2%影响可以忽略不计，但在高指数晶面如{113}上生长显著降低了局部断裂厚度。 在所有晶面取向上观察到纳米尺度的生长丘形成。 由于扩散长度直接取决于表面取向，我们将外延厚度的变化与特定生长晶面的低温稳定性以及动力学限制生长丘的平均尺寸相关联。 显示英文摘要

摘要： Low temperature epitaxial breakdown of inhomogeneously strained Si capping layers is investigated. By growing Si films on coherently strained GeSi quantum dot surfaces, we differentiate effects of surface roughness, strain, and growth orientation on the mechanism of epitaxial breakdown. Using atomic force microscopy and high resolution cross-sectional transmission electron microscopy we find that while local lattice strain up to 2% has a negligible effect, growth on higher-index facets such as {113} significantly reduces the local breakdown thickness. Nanoscale growth mound formation is observed above all facet orientations. Since diffusion lengths depend directly on the surface orientation, we relate the variation in epitaxial thickness to the low temperature stability of specific growth facets and on the average size of kinetically limited growth mounds.