Abstract The initial stages of the growth of germanium on the dimer reconstructed Si(100) surface is modelled using molecular dynamics (MD). Pyramidal island structures are observed to form despite MD being carried out at a deposition rate faster than experiment. By an examination of transitions that can occur from intermediate structures that form in the MD simulations, growth mechanisms can be identified. The initial wetting occurs as a result of Ge atoms diffusing into the trenches between the dimer rows. This results in Ge–Ge or Ge–Si dimer chains growing in rows perpendicular to the original Si–Si dimer rows on the surface. It is shown how strained Ge pyramids with square bases can form by diffusing atoms joining together adjacent dimer rows. From these initial square-based structures, complex concerted motions are observed in which atoms in lower layers ‘climb up’ to higher layers. Similar structures grown in the pure Si case exhibit much higher energies barriers for the ‘climbing up’ process indicating that the effect of strain is to reduce the energy barriers for pyramid formation. In addition to the investigation of atomistic growth processes, surface energy effects are also examined, which show that a germanium-covered Si(100) surface containing shallow-angled pyramids is energetically more favourable than that grown as a flat monolayer.

中文翻译：

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Ge在Si上生长的分子动力学模拟

摘要 使用分子动力学 (MD) 对二聚体重建的 Si(100) 表面上锗生长的初始阶段进行建模。尽管 MD 以比实验更快的沉积速率进行，但仍观察到金字塔岛结构的形成。通过检查在 MD 模拟中形成的中间结构可能发生的转变，可以确定生长机制。最初的润湿是 Ge 原子扩散到二聚体行之间的沟槽中的结果。这导致 Ge-Ge 或 Ge-Si 二聚体链在垂直于表面上原始 Si-Si 二聚体行的行中生长。它显示了如何通过扩散将相邻二聚体行连接在一起的原子来形成具有方形基底的应变 Ge 金字塔。从这些最初的基于正方形的结构中，观察到复杂的协同运动，其中较低层的原子“爬升”到较高层。在纯硅情况下生长的类似结构对于“爬升”过程表现出更高的能量势垒，表明应变的影响是降低金字塔形成的能量势垒。除了对原子生长过程的研究之外，还检查了表面能效应，这表明包含浅角金字塔的锗覆盖的 Si(100) 表面在能量上比作为平坦单层生长的表面更有利。