Area-Selective\nAtomic Layer Deposition of Ruthenium\nvia Reduction of Interfacial Oxidation

Achieving atomic-scale precise control over material\nlayering is\ncritical for the development of future semiconductor technology. Area-selective\ndeposition (ASD) has emerged as an indispensable tool for crafting\nsemiconductor components and structures via bottom-up pattern transfer.\nRuthenium has attracted significant interest as a low-resistivity\nconducting material for next-generation interconnect technology. However,\nthe oxidative counter-reactants such as O<sub>2</sub> often used for\natomic layer deposition (ALD) of metallic Ru films result in a considerable\nincrease in contact resistance because of substrate oxidation, limiting\nthe applications of both ALD and ASD of Ru. In this study, Ru ASD\nis demonstrated using two-step ALD with the sequential use of H<sub>2</sub> and O<sub>2</sub> as counter-reactants and dimethylamino-trimethylsilane\n(DMATMS) as a precursor inhibitor. Both theoretical and experimental\nresults demonstrate that in the two-step Ru ALD, the oxide layer can\nbe eliminated via the reduction of the oxidized substrate metal surface\nby the H<sub>2</sub> counter-reactant. This mechanism simultaneously\nfacilitates the adsorption of the Ru precursor (tricarbonyl-(trimethylenemethane)-ruthenium)\nand removal of the surface oxide layer. Consequently, Ru growth is\nsuppressed on the DMATMS-inhibited SiO<sub>2</sub> surface during\nASD, enabling exclusive deposition of Ru on the Mo surface. The currently\nproposed Ru ASD scheme using two-step ALD is highly promising for\ndriving advancements in interconnect technology for commercial applications.