2020/07/28 by Emanuela Schilirò, E. Schilirò, R. Lo Nigro +11 · 1 citation
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Atomic layer deposition #Chemical engineering #Chemistry #Coalescence (physics) #Composite material #Epitaxy #Graphene #Graphene research and applications #Layer (electronics) #Materials science #Metallurgy #Monolayer #Nanotechnology #Nucleation #Optics #Optoelectronics #Oxide #Raman spectroscopy #Semiconductor materials and devices #Silicon #Silicon carbide #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.carbon.2020.07.069
published as Carbon 169 (2020) 172-181 · 19 pages, 6 figures
arxiv created 2020/07/28 · openalex publication_date 2020/08/01 · openalex created_date 2020/08/03 · arxiv updated 2020/08/18 · openalex updated_date 2026/08/05
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.