Reproducibility and stability of nanoporous SiO2 thin film coatings

In this study, single layer antireflection (AR) coatings have been realized using nanoporous SiO₂ thin films made by atomic layer deposition (ALD) and wet chemical etching. The run-to-run and etch-to-etch reproducibility of nanoporous coatings have been monitored nearly one year. Excellent reproducibility of the film thickness and refractive index, and accordingly of the optical function are demonstrated. Furthermore, the stability of the coatings in vacuum as well as at 200°C has been analyzed.