Selective Aqueous Chemical Solution Deposition Using Patterned Self-Assembling Monolayers.

Bottom-up fabrication techniques, such as Selective Area Deposition, have gained attention in the field of nanotechnology due to their ability to unlock novel structures as well as improve sustainability in fabrication; however, these techniques are incompatible with sustainable chemical solution deposition techniques. In this paper, a novel selective area deposition technique is introduced that is compatible with chemical solution deposition. This new technique combines the utility of selective area deposition with established solution-based film deposition. Using the deposition of barium titanate as a model system, an aqueous precursor solution with high selectivity for the hydrophilic regions was successfully deposited on a hydrophobic/hydrophilic patterned Pt/Si substrate. The substrate was coated with a hydrophobic 1-octadecanethiol self-assembling monolayer that was selectively oxidized by exposure to UV-generated reactive oxygen species. The oxidized molecules were dissolved in ethanol to recover the hydrophilic Pt surface before depositing the precursor solution. The spin-coated precursor solution showed great selectivity for the exposed regions of the substrate after a 25 min UV exposure. The deposited barium titanate test structures were recognizably stripe-like down to a feature size of 27.8 μm, and the smallest recognizable feature size achieved was 15.6 μm, offering potential as a sustainable micropatterning process for films deposited by CSD.