Titanium nitride and silicon nitride films grown by pulsed laser deposition

Titanium nitride, silicon nitride, and their multilayered films grown on Si (100) by Pulsed Laser Deposition (PLD) have been studied. The crystal structure and orientation of films were investigated by XRD and TEM. Titanium nitride film produced at room temperature was a polycrystal with 0.426 nm lattice constant whereas silicon nitride film grown at same condition was the amorphous. Particulates, one of the disadvantages of the PLD technique, were examined in the silicon nitride films varying the laser energy density, the repetition rate, and the target-substrate distance. The effect of laser ablation on the target was studied by SEM and XPS. The silicon nitride target after ablation for 25,000 pulses at Ed = 2.5 J/cm² produced nitrogen-deficient cones that were aligned along the direction of the incident laser beam. The hardness and elastic modulus of the films grown at room temperature in vacuum and at 500 °C in nitrogen background gas (10^-3 torr) were determined using the Nano Indenter®II. The highest hardness and elastic modulus in this study were obtained from the TiN film grown at room temperature in vacuum: 26.44 GPa and 265 GPa, respectively. Multi-layered films consisting of titanium nitride and silicon nitride films had intermediate hardness values. Titanium nitride and silicon nitride film grown at different temperature and pressure were examined by XPS to determine the effect of nitrogen content in films on the hardness. The more nitrogen the higher the hardness for both titanium nitride and silicon nitride films, regardless of deposition temperature.