Beneq is using VTT´s PillarHall(TM) test chip for testing extreme ALD conformality in high aspect ratio structures and has publish a excellent report on their research in the Beneq Science Letter. Please visit PillarHall for full details on how to get involved in testing yourself!
Atomic layer deposition into ultra-high aspect ratio structures with a stop-flow ALD reactor
The structures requiring conformal thin films are continuously becoming more demanding. New technical solutions are needed to meet the requirements. Here the growth of ALD Al2O3 and TiO2 in ultra-high aspect ratio structures is shown with a Beneq TFS 200 ALD reactor equipped with a high aspect ratio stop-flow module. The highest achieved aspect ratios for ALD Al2O3 and TiO2 films were 1:3000 and 1:2000.
Full paper: LINK