Wire grid polarizers (WGPs), periodic nano‐optical metasurfaces, are convenient polarizing elements for many optical applications. However, they are still inadequate in the deep ultraviolet spectral range. It is shown that to achieve high performance ultraviolet WGPs a material with large absolute value of the complex permittivity and extinction coefficient at the wavelength of interest has to be utilized. This requirement is compared to refractive index models considering intraband and interband absorption processes. It is elucidated why the extinction ratio of metallic WGPs intrinsically humble in the deep ultraviolet, whereas wide bandgap semiconductors are superior material candidates in this spectral range. To demonstrate this, the design, fabrication, and optical characterization of a titanium dioxide WGP are presented. At a wavelength of 193 nm an unprecedented extinction ratio of 384 and a transmittance of 10% is achieved.

${\mathrm{Al}}_2{\mathrm{O}}_3$ and ${\mathrm{TiO}}_2$ thin films have been deposited on Si wafers, quartz, BK7 glass, and polycarbonate substrates by atomic layer deposition (ALD). The refractive indices and growth rates of the materials have been determined by spectroscopic ellipsometry and transmission electron microscopy. The influence of substrate temperature and precursor on the refractive indices has been investigated. The refractive index of ${\mathrm{TiO}}_2$ significantly increases with temperature, whereas the ${\mathrm{Al}}_2{\mathrm{O}}_3$ films are temperature insensitive. The films deposited using ${\mathrm{H}}_2{\mathrm{O}}_2$ as oxygen source show a slightly higher refractive index than the films prepared with ${\mathrm{H}}_2\mathrm{O}$. Multilayer narrow-bandpass filters and broadband antireflective coatings have been designed and produced by ALD.

Oxide and nitride thin-films of Ti, Hf and Si serve numerous applications owing to the diverse range of their material properties. It is therefore imperative to have proper control over these properties during materials processing. Ion-surface interactions during plasma processing techniques can influence the properties of a growing film. In this work, we investigated the effects of controlling ion characteristics (energy, dose) on the properties of the aforementioned materials during plasma-enhanced atomic layer deposition (PEALD) on planar and 3D substrate topographies. We used a 200 mm remote PEALD system equipped with substrate biasing to control the energy and dose of ions by varying the magnitude and duration of the applied bias, respectively, during plasma exposure. Implementing substrate biasing in these forms enhanced PEALD process capability by providing two additional parameters for tuning a wide range of material properties. Below the regimes of ion-induced degradation, enhancing ion energies with substrate biasing during PEALD increased the refractive index and mass density of TiO_x and HfO_x and enabled control over their crystalline properties. PEALD of these oxides with substrate biasing at 150 °C led to the formation of crystalline material at the low temperature, which would otherwise yield amorphous films for deposition without biasing. Enhanced ion energies drastically reduced the resistivity of conductive TiN_x and HfN_x films. Furthermore, biasing during PEALD enabled the residual stress of these materials to be altered from tensile to compressive. The properties of SiO_x were slightly improved whereas those of SiN_x were degraded as a function of substrate biasing. PEALD on 3D trench nanostructures with biasing induced differing film properties at different regions of the 3D substrate. Based on the results presented herein, prospects afforded by the implementation of this technique during PEALD, such as enabling new routes for topographically selective deposition on 3D substrates, are discussed.