Effect of the plasma parameters on the properties of titanium nitride thin films grown by laser ablation

Abstract

Titanium nitride thin films were deposited at low temperatures (less than 250 °C) using the laser ablation technique. The effect of both the laser beam energy density and the gas pressure on the plasma parameters was studied. The film structure, mechanical properties and surface morphology were investigated as a function of the plasma parameters. The results showed a strong dependence of these properties on the ion kinetic energy and plasma density. The gas pressure was seen to control the preferred orientation of the films in the (200) and (111) directions. At 1×10-2 Torr only the (200) direction was observed. In addition, the crystal size for all the films was found to depend on the plasma parameters; generally, an increase of ion energy and plasma density resulted in a decrease of the crystal size. TiN films with hardness as high as 24.0 GPa, which is suitable for many mechanical applications, were obtained. The hardness was strongly affected by the ion energy, increasing as the ion energy increased. These results show that the properties of the deposited material are controlled in part by the degree of ion bombardment and the plasma density.