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).

Controlling the Plasmonic Properties of Ultrathin TiN Films at the Atomic Level

“…Three peaks can be used to fit the N 1s spectrum, where the dominant peak at 396.8 eV is attributed to Ti-N bonds. The peak at 397.7 eV is due to the formation of an oxynitride compound, resulting in Ti-O-N bonds31,32 . An additional weak peak in the fitting is observed at a lower energy 395.8, which may be the result of other impurities or nitrogen chemically bonded on the surface32,33 .…”

“…The peak at 397.7 eV is due to the formation of an oxynitride compound, resulting in Ti-O-N bonds31,32 . An additional weak peak in the fitting is observed at a lower energy 395.8, which may be the result of other impurities or nitrogen chemically bonded on the surface32,33 . While evidence of TiN x O y is also present in the O 1s spectrum (531.2 eV), the main peak at 529.9 eV is indicative of the existence of Ti-O bonds in the films34 .…”

Titanium nitride as light trapping plasmonic material in silicon solar cell

“…Therefore, Titanium Nitride (TiN) has sparked as a potential candidate for broadband absorption covering the entire visible-infrared regions of the electromagnetic spectrum with a surplus benefits such as low loss and cost, high thermal and oxidative stability, unlike Au and Ag. TiN is fully compatible with the existing CMOS fabrication techniques in addition TiN exhibits biocompatibility [19,31,32,33].…”

Flat Optical and Plasmonic Devices Using Area‐Selective Ion‐Beam Doping of Silicon

“…Materials such as conducting nitrides and oxides and traditional group IV and III–V semiconductors can have doping‐tunable plasma wavelengths spanning the infrared spectrum, and have become promising for plasmonics applications. Some of these materials, e.g., titanium nitride, have the added benefit of high‐temperature resistance and CMOS compatibility .…”

“…Some of these materials, e.g., titanium nitride, have the added benefit of high‐temperature resistance and CMOS compatibility . Prior work using these materials mainly involves uniformly doped substrates, films, or nanocrystals, and structuring is usually achieved through selective etching …”