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Title: Roll-to-roll atomic layer deposition process for flexible electronics encapsulation applications

At present flexible electronic devices are under extensive development and, among them, flexible organic light-emitting diode displays are the closest to a large market deployment. One of the remaining unsolved challenges is high throughput production of impermeable flexible transparent barrier layers that protect sensitive light-emitting materials against ambient moisture. The present studies deal with the adaptation of the atomic layer deposition (ALD) process to high-throughput roll-to-roll production using the spatial ALD concept. We report the development of such a process for the deposition of 20 nm thickness Al{sub 2}O{sub 3} diffusion barrier layers on 500 mm wide polymer webs. The process uses trimethylaluminum and water as precursors at a substrate temperature of 105 °C. The observation of self-limiting film growth behavior and uniformity of thickness confirms the ALD growth mechanism. Water vapor transmission rates for 20 nm Al{sub 2}O{sub 3} films deposited on polyethylene naphthalate (PEN) substrates were measured as a function of substrate residence time, that is, time of exposure of the substrate to one precursor zone. Moisture permeation levels measured at 38 °C/90% relative humidity by coulometric isostatic–isobaric method were below the detection limit of the instrument (<5 × 10{sup −4} g/m{sup 2} day) for films coated at web moving speed of 0.25 m/min. Measurements using themore » Ca test indicated water vapor transmission rates ∼5 × 10{sup −6} g/m{sup 2} day. Optical measurements on the coated web showed minimum transmission of 80% in the visible range that is the same as the original PEN substrate.« less
Authors:
; ; ;  [1] ; ;  [2] ; ;  [3] ; ;  [4]
  1. Advanced Surface Technology Research Laboratory, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland)
  2. Beneq Oy, P.O. Box 262, 01511 Vantaa (Finland)
  3. Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 589, 33101 Tampere (Finland)
  4. Samsung Cheil Industries, San Jose R and D Center, 2186 Bering Drive, San Jose, California 95131 (United States)
Publication Date:
OSTI Identifier:
22317970
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 32; Journal Issue: 5; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM OXIDES; DEPLETION LAYER; DEPOSITION; ELECTRONIC EQUIPMENT; ENCAPSULATION; LIGHT EMITTING DIODES; POLYETHYLENES