High Performance Moisture Barrier Films Deposited with ALD Manufacturing Equipment

A ~ 10 nm thick Al 2 O 3 passivation layer (pre-encapsulation) was depo- sited on top of 150 nm thick Ca pads with ALD at TU Braunschweig in an inert atmosphere. The passivated Ca substrates were subsequently shipped to Beneq in Finland, where nanolaminate barrier fi lms stacks were deposited using ALD at 100 ºC. The ALD deposition was made in a Beneq P400 type batch ALD equipment, similar to those used in ma- nufacturing of more than 2 million inorganic thin-fi lm (TFEL) displays during the last twenty years. Two types of barrier fi lms were deposi- ted. One was the same Al 2 O 3 /ZrO 2 nanolaminate barrier fi lms reported in ref. 2 , which was made using water, trimethyl aluminium (TMA) and tetrakis(dimethylamido)zirconium (TDMA(Zr)) as precursors. The to- tal thickness of the nanolaminate was about 130 nm. The other nano- laminate was made using another, more cost effective ALD process without the TDMA precursor. The total thickness was approx. 100 nm. A schematic drawing of the cross-section of the samples is shown in fi gure 1. The samples were subsequently sent to TU Braunschweig, where the samples were put in a chamber at 80 °C, 80% RH. The WVTR value was estimated based on the change in resistivity of Ca as shown in fi gure 2.