Synergy between Plasma-Assisted ALD and Roll-to-Roll Atmospheric Pressure PE-CVD Processing of Moisture Barrier Films on Polymers

Abstract

The synergy between fast (1600 nm · min-1), roll-to-roll plasma-enhanced chemical vapor deposited (PE-CVD) SiO2 layers and plasma-assisted atomic layer deposited (PA-ALD) ultra-thin Al2O3 films has been investigated in terms of moisture permeation barrier properties. The effective and intrinsic water vapor transmission rates (WVTR) were studied as a function of the number of ALD cycles. It was demonstrated that a synergistic combination of a silica buffer layer deposited on polymer with an ultra-thin (≤ 2 nm) alumina barrier film can provide excellent intrinsic (10-5-10-6 g · m-2 · day-1) and good effective (∼10-3 g · m-2 · day-1) WVTR values, whereas both single layers individually exhibit poor barrier performances with effective WVTR values of ≥ 1.0 g · m-2 · day-1. The article studies synergistic effect in combining industrially compatible roll-to-roll atmospheric pressure PE-CVD and plasma-assisted ALD technologies for moisture barrier fabrication on polyethylene 2,6 naphthalate (PEN) polymer. It is demonstrated that enhancement of polymer substrate with silica-like PE-CVD buffer layer enables ultra-thin Al2O3 barrier films produced already by 10-15 plasma-assisted ALD cycles.