Surface modification method using rare-earth oxide thin films

Heat-Resistant Hydrophobic Surface Modification Using Plasma-Enhanced Atomic Layer Deposition of Yttrium Oxide Thin Films

This technology modifies hydrophilic surfaces—such as silicon, silica, and platinum—into hydrophobic surfaces by depositing a 20 nm thick yttrium oxide (Y2O3) thin film using plasma-enhanced atomic layer deposition (PE-ALD). The thin film is grown by repeating the adsorption of an yttrium precursor followed by an oxygen plasma reaction.

Conventional silicon-based inorganic and organic polymer modifiers suffer from low thermal stability, causing them to lose their hydrophobicity at high temperatures. This limitation has made them difficult to apply in fields requiring high heat resistance, such as jet engine components or fire-resistant glass.

By using a thermally stable rare-earth oxide as the modification layer and depositing it thinly and uniformly via PE-ALD, this technology achieves a heat-resistant hydrophobic surface without damaging the underlying substrate. Water contact angles increase from 31.6° to 80.2° for silicon, 20.2° to 71.2° for silica, and 67.6° to 84.2° for platinum, with final hydrophobicity adjustable by substrate selection. Applicable to water-repellent glass, metal wiring, semiconductor substrates, and jet engine parts, it provides a coating solution that maintains water repellency even in high-temperature environments.

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Key Features:

• Removing the native oxide layer from hydrophilic silicon, silica, and platinum substrates and heating them to 300°C
• Adsorbing vaporized yttrium precursor onto the substrate with argon carrier gas and purging excess precursor with argon
• Reacting the adsorbed yttrium precursor with inductively coupled oxygen plasma to form a yttrium oxide thin film, repeating the process until a 20 nm thickness is reached
• A surface modification method that increases contact angles to 80.2° for silicon, 71.2° for silica, and 84.2° for platinum, for use in water-repellent glass, semiconductor substrates, and jet engine components

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This invention was developed with support from the Small and Medium Business Administration for the development of superhydrophobic ceramic functional coatings using nanopowder coating technology.

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