Gas diffusion barriers on polymers using Al2O3 atomic layer deposition

TLDR

The study examined Al₂O₃ ALD thin films as gas diffusion barriers on flexible polyethylene naphthalate and Kapton polyimide substrates. Al₂O₃ films of 1–26 nm were deposited by ALD at 100–175 °C. Al₂O₃ films ≥5 nm achieved oxygen transmission rates below 5 × 10⁻³ cc m⁻² day⁻¹, while 26 nm films exhibited H₂O vapor transmission of ~1 × 10⁻³ g m⁻² day⁻¹, indicating that ultrathin ALD barriers could enable flexible polymer‑based displays and electronics.

Abstract

Thin films of Al2O3 grown by atomic layer deposition (ALD) were investigated as gas diffusion barriers on flexible polyethylene naphthalate and Kapton® polyimide substrates. Al2O3 ALD films with thicknesses of 1–26nm were grown at 100–175°C. For Al2O3 ALD films with thicknesses ⩾5nm, oxygen transmission rates were below the MOCON instrument test limit of ∼5×10−3cc∕m2∕day. Applying a more sensitive radioactive tracer method, H2O-vapor transmission rates of ∼1×10−3g∕m2∕day were measured for single-sided Al2O3 ALD films with thicknesses of 26nm on the polymers. Ultrathin gas diffusion barriers grown by Al2O3 ALD may enable organic displays and electronics on permeable, flexible polymer substrates.