Atomic Layer Modulation of Multicomponent Thin Films through Combination of Experimental and Theoretical Approaches

We proposed the concept of atomic layer modulation (ALM) based on precursor chemical reactivities and steric hindrance effects to fabricate multicomponent nanofilms. Because ALM employs consecutive precursor exposures followed by exposure to a counter reactant, the composition of ALM films is determined by the molecular size and chemical reactivities of the precursors. For the demonstration, dicarbonyl-bis(5-methyl-2,4-hexanediketonato)Ru(II) (Carish) and trimethylaluminum (TMA) were used as Ru and Al precursors, respectively, and H2O was used as the counter reactant. Prior to the experiments, the chemical reactivity and sterically hindered physisorption of the Ru and Al precursors were theoretically calculated using density functional theory (DFT) and Monte Carlo (MC) simulations, respectively. The transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) results were highly consistent with the theoretical results, and the growth characteristics were well explained by the MC- and DFT-based reaction models. We believe that ALM could be extended to other material systems, thereby providing a different method of fabricating multicomponent nanofilms for various applications including semiconductors and nanodevices.