Hydrophobicity of Rare Earth Oxides Grown by Atomic Layer Deposition

Abstract

Rare earth oxide (REO) atomic layer deposition (ALD) processes are investigated for hydrophobic coatings. Thermal and plasmaenhanced ALD (PE-ALD) Er 2 O 3 and Dy 2 O 3 are developed using the newly synthesized Er and Dy precursors bis-methylcyclopentadienyl-diisopropylacetamidinate-erbium and bis-isopropylcyclopentadienyl-diisopropyl-acetamidinate-dysprosium, with H 2 O and O 2 plasma counter oxidants. The Er and Dy precursors show typical ALD growth characteristics with no nucleation incubation, indicating that they are suitable ALD precursors. The hydrophobicities of ALD-grown Er 2 O 3 and Dy 2 O 3 are investigated, together with those of ALD-grown Y 2 O 3 , La 2 O 3 , and CeO 2 that were previously developed for high-k applications. All the ALD-grown REOs show high hydrophobicity, with water contact angles as high as 90°. After annealing at 500 °C in air for 2 h, hydrophobicity is degraded depending on the kind of material; this degradation is related to the hygroscopy of REOs. In addition, we demonstrate the fabrication of a superhydrophobic surface by depositing highly conformal ALD REO films on 3D Si nanowire nanostructures. The Si NWs are conformally coated with ALD Y 2 O 3 , yielding a surface with a water contact angle of about 158°. The ALD REOs reported herein should find widespread applicability in the fabrication of robust hydrophobic coatings.

Water assisted atomic layer deposition of yttrium oxide using tris(N,N′-diisopropyl-2-dimethylamido-guanidinato) yttrium(iii): process development, film characterization and functional properties

“…[1][2][3] Moreover, a high thermal conductivity of 0.27 W (cm K) À1 at 300 K, 4 a high melting point of 2430 C and a high mechanical strength make this material conducive for other solid state applications, 5,6 such as temperature and wear resistive coatings and hydrophobic house hold coatings. 7 To meet the demands for smaller, yet more effective transistors, the thickness of the functional layers in these transistors has to shrink. To retain the performances of the transistor and hinder tunnelling-effects in the thin dielectric material, high-k gate dielectrics must be employed.…”

Non-fluorinated superhydrophobic and micro/nano hierarchical Al doped ZnO film: the effect of Al doping on morphological and hydrophobic properties

“…[1][2][3] As is well known, superhydrophobicity is based on the combination of suitable rough topography and low surface energy. 6 Therefore, increasing attention is drawn to fabricating superhydrophobic surfaces without any low energy organic materials, such as inorganic material lms with specic hierarchical rough surfaces. 4,5 However, the organic modied coatings are expensive, unstable and easily contaminated in their practical applications.…”

A robust quasi‐superhydrophobic ceria coating prepared using air‐plasma spraying

“…Moreover, the coating can maintain hydrophobicity even after annealed at high temperature. This is because the bond coat circumvents the problem that the coating is spalled after high‐temperature annealing, which derives from considerable mismatch of the thermal expansion coefficients between ceramic and substrate . Hence, the robust APS ceria coating exhibits good thermal stability, which shows promising potential in the application of hydrophobic coating undergoing harsh temperature variation.…”

“…Zenkin et al fabricated REOs films using sputtering. Oh et al employed atomic layer deposition technique to prepare hydrophobic REOs film. Cho et al prepared REOs by hydrothermal method.…”