Study of initial growth of Cu on SiO_2 and 3-mercaptopropyltrimethoxysilane-coated SiO_2

摘要

The initial growth of Cu by sputtering on SiO_2 and 3-mercaptopropyltrimethoxysilane (MPTMS)-modified SiO_2 was studied using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The initial growth of Cu on both substrates exhibited the 3D-island mode. On the SiO_2 surface, Cu after 2.5 ML deposition existed as spherical nanoparticles at a number density of 1.3 * 10~(16) m~(-2), indicating high mobility of Cu on the substrate surface. On the MPTMS-modified SiO_2 surface, Cu after 2.5 ML deposition preferentially grew on the areas covered with polymerized MPTMS aggregates at a higher number density of 3.9 * 10~(16) m~(-2), indicating limited mobility of Cu on the substrate surface. The strong interaction between Cu and the uppermost sulfur of polymerized MPTMS aggregates on SiO_2 is responsible for the difference in initial growth of Cu on SiO_2 and MPTMS-modified SiO_2.