(360c) Small Molecule Inhibitors As Universal Resists for Area-Selective Atomic Layer Deposition.

Area-selective atomic layer deposition (AS-ALD) is a promising technique for atomically precise, self-aligned fabrication of next-generation electronic, photonic, and quantum devices. It offers higher resolution than traditional top-down micromachining, particularly for 3D integrated circuits. AS-ALD relies on selective deposition on growth (GS) and non-growth surfaces (NGS), with selectivity achieved either by leveraging material surface differences or applying resist layers that block deposition. However, selectivity decreases over time as growth occurs on NGS, requiring strategies like more durable resists or periodic resist regeneration. Common resists include polymeric and inorganic films applied via lithography, which undermines AS-ALD’s resolution potential and complicates integration with ALD. Self-assembled monolayers (SAMs) offer some advantages but are limited by their size, removal difficulty, incompatibility with ALD, and sensitivity to surface defects.

To address these limitations, we investigate the mechanism of atomic layer deposition of metal oxides on Small Molecule Inhibitors (SMI) resists. SMIs are a novel class of ALD resists that can potentially achieve higher spatial resolution and better compatibility with a wider variety of substrates and ALD chemistries than traditional polymer and SAMs resists. Our SMI resists rely on universal small-molecule meta-stable species – carbenes and nitrenes – instead of substrate-specific resists that are currently being tested. The high reactivity of these species (that can be produced both thermally and photochemically) overcomes the diffusion problems with resist deposition and regeneration and makes them applicable to a variety of materials. Because SMI resists do not rely on self-assembly for structural stability, they can be applied on interfaces with higher density of surface defects without compromising coverage or ALD selectivity.