Fabrication and properties of plasmonic crystalline thin film of titanium nitride (TiN) by pulsed laser deposition with Nd:YAG laser at 355 nm

Abstract

For efficient plasmonic MIM structures in fabrication of optical nano-probe tip for scanning near-field microscope (SNOM), an experimental study of thin film fabrication of titanium nitride (TiN) has been started by pulsed laser deposition (PLD) with 3rd harmonic (355nm) pulses of high-power Nd:YAG laser. Inside a TMP-pumped UHV chamber, a TiN powder sintered body has been irradiated with the UV laser pulses (3.3 nsFWHM, 10Hz, up to 340mJ/ pulse on target) at different intensities and incident angles. The deposited films on glass slide or silicon wafer has been analyzed by X-ray diffractometer (XRD), UV-Vis spectrophotometer, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). Previously-reported PLD fabrication experiments for TiN film used a titanium (Ti) target with several gas species including nitrogen. The laser-produced Ti plasma with an appropriate condition had a chemical reaction with nitrogen molecules, and the resultant TiN film was deposited on a substrate. While on the other hand, this study has significant features of (1) PLD target made of crystalline powder sintered body and (2) UV laser pulses having temporally-smoothed gaussian profile by injection-seeding of IR laser diode beam. The very first trial depositions have succeeded to fabricate flat and dense films of a few hundred nm, which were partly covered with debris and cracks. The resultant XRD pattern of film having luster of gold indicated several peaks including 42.6° (200) and 61.8° (220) which correspond to crystal structure of TiN. The electron configuration in the PLDed TiN film is studied using XPS.