论文标题
在外延石墨烯上原子层沉积早期的氧化铝核定量
Aluminum oxide nucleation in the early stages of atomic layer deposition on epitaxial graphene
论文作者
论文摘要
在这项工作中，已经通过原子力显微镜（AFM）和Raman光谱研究了，已经研究了碳化硅（4H-SIC）对单层外延石墨烯（EG）在单层外延石墨烯（例如4H-SIC）上直接原子层沉积（ALD）早期的成核和生长机制。与其他类型的石墨烯通常观察到的相反，在EG的情况下，观察到了成核位点的较大和均匀的密度，并归因于EG/SIC界面处的缓冲层的存在。沉积过程的特征是在很早的阶段，Al2O3岛的生长，随后仅由于岛屿结合而形成了40个ALD周期，并形成连续的Al2O3膜（2.4 nm厚），随后逐层生长。拉曼光谱分析显示ALD过程对EG的缺陷密度和掺杂的影响很小。 EG菌株在岛屿生长和结合方面的沉积也几乎不受影响，而在紧凑的AL2O3膜形成后，观察到显着增加。获得的结果可能对需要整合超薄高K绝缘子的外延石墨烯的设备应用具有重要意义。
In this work, the nucleation and growth mechanism of aluminum oxide (Al2O3) in the early stages of the direct atomic layer deposition (ALD) on monolayer epitaxial graphene (EG) on silicon carbide (4H-SiC) has been investigated by atomic force microscopy (AFM) and Raman spectroscopy. Contrary to what is typically observed for other types of graphene, a large and uniform density of nucleation sites was observed in the case of EG and ascribed to the presence of the buffer layer at EG/SiC interface. The deposition process was characterized by Al2O3 island growth in the very early stages, followed by the formation of a continuous Al2O3 film (2.4 nm thick) after only 40 ALD cycles due to the islands coalescence, and subsequent layer-by-layer growth. Raman spectroscopy analyses showed low impact of the ALD process on the defects density and doping of EG. The EG strain was also almost unaffected by the deposition in the regime of island growth and coalescence, whereas a significant increase was observed after the formation of a compact Al2O3 film. The obtained results can have important implications for device applications of epitaxial graphene requiring the integration of ultra-thin high-k insulators.
