Research of Atomic Layer Deposited HfO2/TiO2 Multilayer Structures by Spectroscopic and Multiangle Monochromatic Null Ellipsometry

The HfO
₂
/TiO
₂
multilayers with different bilayer period, which are currently used as dielectrics in modern microelectronics, were deposited by atomic layer deposition (ALD). The complementary ellipsometric techniques were applied to measure the thickness and describe the optical properties of the stacks and superlattices deposited. A nonmonotonic dependence of the effective refractive index on the number of each layer ALD-cycles was shown. The approach suggested can be useful for the similar ALD-processes and for further studies of the properties of dielectrics. The data obtained give important information about the features of Hf02 and TiO
₂
nucleation during alternate layers growth.