Flexible Gas Diffusion Barriers Using ALD/MLD Multilayers and Roll-to-Roll Processing

ALD NanoSolutions, Inc. is developing flexible gas diffusion barriers to enable FOLEDs, thin film photovoltaics and other devices to be fabricated on polymer substrates in a novel roll-to-roll ALD process. Multilayer barriers films consisting of nanometer thick inorganic and organic layers can be fabricated using atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques. By interspersing the already excellent nanometer thick Al2O3 ALD barrier films with thin, flexible polymeric MLD layers, we can create flexible ultrabarriers. The very low water vapor transmission rates (WVTR) of these ALD/MLD film will be tested using our improved Calcium test. Flexibility of these ALD/MLD multilayer films will be characterized using advanced cracking detection methods and optimized using modeling of the strains in multilayer film stacks. Meeting the aggressive Phase II targets of<1x10-6 g/m2/day WVTR and 5% strain requires a combination of a thorough understanding of the mechanics of a multilayer films, the precise control afforded by ALD/MLD techniques, and advanced testing and characterization methods. Commercialization of these ALD/MLD ultrabarriers will be developed in pilot scale roll-to-roll ALD processing. Using our initial proof-of-concept work, we will build a continuous, multi-cycle, atmospheric ALD deposition head to pioneer ALD on a moving flexible web substrate.