Atmospheric pressure plasma enhanced spatial atomic layer deposition of SnO_x as conductive gas diffusion barrier Available to Purchase

The authors report the preparation of transparent conductive gas permeation barriers based on thin films of tin oxide (SnO_x) grown by spatial atomic layer deposition (ALD) at atmospheric pressure. They present a comparative study using tetrakis(dimethylamino)tin(IV) and various oxidants (atmospheric pressure oxygen plasma, ozone, and water) at process temperatures in the range of 80–165 °C. Specifically, for oxygen plasma or ozone as oxidant, the authors confirm self-limited ALD growth with a growth per cycle (GPC) of 0.16 and 0.11 nm for 80 and 150 °C, respectively, comparable to the classical vacuum-based ALD of SnO_x. On the contrary, for water-based processes the GPC is significantly lower. Very notably, while SnO_x grown with water as oxidant shows only a very limited electrical conductivity [10⁻³ (Ω cm)⁻¹], atmospheric pressure oxygen plasma affords SnO_x layers with an electrical conductivity up to 10² (Ω cm)⁻¹. At the same time, these layers are excellent gas permeation barriers with a water vapor transmission rate as low as 7 × 10⁻⁴g m⁻²day⁻¹ (at 60 °C and 60% rH). ALD growth will be demonstrated at substrate velocities up to 75 mm/s (i.e., 4.5 m/min), which renders spatial plasma assisted ALD an excellent candidate for the continuous manufacturing of transparent and conductive gas permeation barriers based on SnO_x.