Optimization of sputtered titanium nitride as a tunable metal for plasmonic applications

Abstract

Alternative materials for plasmonic devices have garnered much recent interest. A promising candidate material is titanium nitride. Although there is a substantial body of work on the formation of this material, its use for plasmonic applications requires a more systematic and detailed optical analysis than has previously been carried out. This paper describes an initial optimization of sputtered TiN thin films for plasmonic performance from visible into near-IR wavelengths. The metallic behavior of TiN films exhibits a sensitive dependence on the substrate and deposition details. We explored reactive and non-reactive sputter deposition of TiN onto various substrates at both room temperature and 600°C. Metallic character was compared for films grown under different conditions via spectroscopic ellipsometry and correlated with compositional and structural measurements via x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), and scanning transmission electron microscopy (STEM).