Alcohol-Mediated Area-Selective Atomic Layer Deposition through Surface Chemical States Modulation

Area-selective atomic layer deposition (AS-ALD) fundamentally relies on a distinct disparity in surface chemical states between growth and nongrowth area. For SiO2/Cu patterned architectures, the oxidation of the Cu surface serves as a primary driver for the loss of selectivity as the ALD process proceeds. Herein, an alcohol-mediated AS-ALD process is proposed, utilizing alcohols with varying carbon chain lengths to precisely modulate surface chemical states to enhance selectivity of AS-ALD WOx film. A competitive-synergistic mechanism involving surface reductive capability and steric hindrance is identified as the governing factor for process selectivity. Results demonstrate that while the reducing ability of alcohols on oxidized Cu surfaces diminishes with increasing carbon chain length, their steric hindrance increases. EtOH was identified as the optimal pretreatment agent, yielding an exceptional selectivity exceeding 99.9% on SiO2/Cu patterned surface. Moreover, the alcohol-mediated AS-ALD process is successfully extended to other oxide systems with precursors bearing analogous ligands, demonstrating the generality of the proposed strategy. This work provides a versatile methodology for modulating surface reductive capability and steric hindrance to achieve high-selectivity AS-ALD.