Thermal Atomic Layer Deposition of Yttrium Oxide Films and Their Properties in Anticorrosion and Water Repellent Coating Applications

• Main Authors: Christian Dussarrat, Nicolas Blasco, Wontae Noh, Jooho Lee, Jamie Greer, Takashi Teramoto, Sunao Kamimura, Nicolas Gosset, Takashi Ono
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Coatings
• Subjects: heteroleptic precursor; thermal atomic layer deposition; yttrium oxide; plasma-resistant coating; water contact angle
• Online Access: https://www.mdpi.com/2079-6412/11/5/497

The thermal atomic layer deposition (ThALD) of yttrium oxide (Y₂O₃) was developed using the newly designed, liquid precursor, Y(EtCp)₂(<i>ⁱ</i>Pr₂-amd), as the yttrium source in combination with different oxygen sources, such as ozone, water and even molecular oxygen. Saturation was observed for the growth of the Y₂O₃ films within an ALD window of 300 to 450 °C and a growth per cycle (GPC) up to 1.1 Å. The resulting Y₂O₃ films possess a smooth and crystalline structure, while avoiding any carbon and nitrogen contamination, as observed by X-ray photoelectron spectroscopy (XPS). The films showed strong resistance to fluorine-containing plasma, outperforming other resistant materials, such as silicon oxide, silicon nitride and alumina. Interestingly, the hydrophilic character exhibited by the film could be switched to hydrophobic after exposure to air, with water contact angles exceeding 90°. After annealing under N₂ flow at 600 °C for 4 min, the hydrophobicity was lost, but proved recoverable after prolonged air exposure or intentional hydrocarbon exposure. The origin of these changes in hydrophobicity was examined.