Gas diffusion ultrabarriers on polymer substrates using Al 2 O 3 atomic layer deposition and SiN plasma-enhanced chemical vapor deposition

• Published in: Journal of applied physics 2009-07, Vol.106 (2), p.023533-023533-6
• Main Authors: Carcia, P. F., McLean, R. S., Groner, M. D., Dameron, A. A., George, S. M.
• Format: Article
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3159639

Thin films grown by Al 2 O 3 atomic layer deposition (ALD) and SiN plasma-enhanced chemical vapor deposition (PECVD) have been tested as gas diffusion barriers either individually or as bilayers on polymer substrates. Single films of Al 2 O 3 ALD with thicknesses of ≥ 10   nm had a water vapor transmission rate (WVTR) of ≤ 5 × 10 − 5   g / m 2 day at 38 ° C / 85 % relative humidity (RH), as measured by the Ca test. This WVTR value was limited by H 2 O permeability through the epoxy seal, as determined by the Ca test for the glass lid control. In comparison, SiN PECVD films with a thickness of 100 nm had a WVTR of ∼ 7 × 10 − 3   g / m 2 day at 38 ° C / 85 % RH. Significant improvements resulted when the SiN PECVD film was coated with an Al 2 O 3 ALD film. An Al 2 O 3 ALD film with a thickness of only 5 nm on a SiN PECVD film with a thickness of 100 nm reduced the WVTR from ∼ 7 × 10 − 3 to ≤ 5 × 10 − 5   g / m 2 day at 38 ° C / 85 % RH. The reduction in the permeability for Al 2 O 3 ALD on the SiN PECVD films was attributed to either Al 2 O 3 ALD sealing defects in the SiN PECVD film or improved nucleation of Al 2 O 3 ALD on SiN.