Defect analysis in low temperature atomic layer deposited Al2O3 and physical vapor deposited SiO barrier films and combination of both to achieve high quality moisture barriers

Al2O3 [20 nm, atomic layer deposition (ALD)] and SiO films' [25 nm, physical vacuum deposition (PVD)] single barriers as well as hybrid barriers of the Al2O3/SiO or SiO/Al2O3 have been deposited onto single 100 nm thick tris-(8-hydroxyquinoline) aluminum (AlQ3) organic films made onto silicon wafers. The defects in the different barrier layers could be easily observed as nonfluorescent AlQ3 black spots, under ultraviolet light on the different systems stored into accelerated aging conditions (85 °C/85% RH, ∼2000 h). It has been observed that all devices containing an Al2O3 layer present a lag time τ from which defect densities of the different systems start to increase significantly. This is coherent with the supposed pinhole-free nature of fresh, ALD-deposited, Al2O3 films. For t > τ, the number of defect grows linearly with storage time. For devices with the single Al2O3 barrier layer, τ has been estimated to be 64 h. For t > τ, the defect occurrence rate has been calculated to be 0.268/cm2/h. Then, a t...