Cryogenic characterization of titanium nitride thin films

It is well known that noble metals are not compatible with silicon fabrication processing due to their low melting point, and that their plasmonic behaviour suffers from the material losses at visible wavelengths. As an alternative, titanium nitride has been highly investigated in order to overcome these challenges. High temperature characterization of TiN films has been performed, showing its CMOS compatibility; however, information on intrinsic losses at lower temperatures is still lacking. Here we experimentally investigate the optical properties of a 100 nm TiN film under low temperatures down to 1.5 K. From the reflection measurements we retrieve the dielectric constant and analyze plasmonic applications possibilities.