Determination of Atomic-Layer-Deposited Multilayer Antireflection Coating Parameters Using a Novel X-Ray Reflectivity Approach

Abstract

Atomic-layer-deposited Al2O3/TiO2/Al2O3 multilayer antireflection stacks used for broadband antireflection coatings were characterized by a novel combination of an X-ray reflectivity layer thickness extraction algorithm and X-ray reflectivity simulations, together with spectroscopic ellipsometry, broadband optical reflectance, glancing incidence X-ray diffraction, transmission electron microscope and energy dispersive X-ray spectroscopy. Layer thicknesses and surface and interface roughnesses or grading with a few angstroms’ precision, and densities with less than one percent uncertainty were assessed. These parameters are key to understanding the role of deposition and processing conditions on the performance of broadband antireflection coatings. Additionally, the effect of air annealing at 400 °Ϲ for 10 min on the structural and optical properties of multilayer Al2O3/TiO2/Al2O3 antireflection coating was revealed with these techniques.