Author:

Keywords:

Science & Technology, Physical Sciences, Technology, Chemistry, Multidisciplinary, Materials Science, Multidisciplinary, Chemistry, Materials Science, atomic layer deposition, growth mechanism, mean field/kinetic Monte Carlo modeling, noble metal, surface dependence, HYDROXYL-GROUPS, FILMS, NUCLEATION, OXIDE, HFO2, ALD, 0306 Physical Chemistry (incl. Structural), 0912 Materials Engineering, 3403 Macromolecular and materials chemistry, 4016 Materials engineering, 5104 Condensed matter physics

Abstract:

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Understanding the growth mechanisms during the early stages of atomic layer deposition (ALD) is of interest for several applications including thin film deposition, catalysis, and area-selective deposition. The surface dependence and growth mechanism of (ethylbenzyl)(1-ethyl-1,4-cyclohexadienyl)ruthenium and O2 ALD at 325 °C on HfO2, Al2O3, OH, and SiOSi terminated SiO2, and organosilicate glass (OSG) are investigated. The experimental results show that precursor adsorption is strongly affected by the surface termination of the dielectric, and proceeds most rapidly on OH terminated dielectrics, followed by SiOSi and finally SiCH3 terminated dielectrics. The initial stages of growth are characterized by the formation and growth of Ru nanoparticles, which is mediated by the diffusion of Ru species. Mean-field and kinetic Monte Carlo modeling show that ALD on OSG is best described when accounting for (1) cyclic generation of new nanoparticles at the surface, (2) surface diffusion of both atomic species and nanoparticles, and (3) size-dependent nanoparticle reactivity. In particular, the models indicate that precursor adsorption initially occurs only on the dielectric substrate, and occurs on the Ru nanoparticles only when these reach a critical size of about 0.85 nm. This phenomenon is attributed to the catalytic decomposition of oxygen requiring a minimum Ru nanoparticle size.