- Journal
- Chemistry of Materials
- Date
- 2023.07.03
- Abstract
Area selective deposition (ASD) using precursor inhibitor (PI) is a promising alternative to self-assembled monolayers (SAMs) inhibitors due to wide range of materials selection and high process compatibility. In this work, the bis？(ethylcyclopentadienyl)-ruthenium Ru(EtCp)2 precursor is introduced as a homometallic PI for the ruthenium (Ru) ASD process. Prior to the experiments, the chemical reactivity and steric hindrance between Ru(EtCp)2 PI, Ru precursor, and H2O reactant were theoretically calculated using density functional theory (DFT) and Monte Carlo (MC) simulations. The results show that the blocking property is related to the packing density of Ru(EtCp)2 PI on the surface, and the unoccupied sites cause the degradation of blocking property. An additional H2O pulse was used to hydrolyze and remove the Et groups of Ru(EtCp)2, creating more space for additional adsorption of Ru(EtCp)2. As a result, the packing density of Ru(EtCp)2 PI is increased, leading to improvement of the blocking property. While a single pulse of Ru(EtCp)2 PI inhibits the growth of Ru ALD film for 200 cycles, the Ru(EtCp)2 with H2O additional pulse inhibits the growth of Ru ALD for up to 300 cycles. Transmission electron microscopy results show that the ASD Ru thin films are pure metallic even after the degradation of Ru(EtCp)2 PI, highlighting the possibility of homometallic PI in future application of metal ASD processes.
- Reference
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