Revealing plasmonic TiN films with low power radio-frequency magnetron sputtering technique

Growth of plasmonic titanium nitride (TiN) film has recently attracted a considerable interest for various applications ranging from biosensing to optoelectronic devices. A room temperature deposition of high-quality TiN films by radio-frequency magnetron sputtering method with 60 W power is presented. Synchrotron based X-ray diffraction confirms the cubic phase formation in these films, while X-ray photoelectron spectroscopy (XPS) supports the existence of Ti-N bonds along with the presence of TiN_xO_y. Atomic force microscopy and scanning electron microscopy further suggest the development of a smooth surface. Optical characterisations by ellipsometry and ultraviolet-visible spectroscopy together establish the plasmonic behaviour of TiN films. A substantial negative value in the real component of the dielectric function is determined, where the partially filled Ti-3d orbitals near the Fermi level is evidenced from the valence band XPS analysis. The observed results therefore confirm that the plasmonic behaviour of the present TiN films is auspicious for (opto)electronic applications.