Enhancement of Mechanical Property on Sputtered TiNx Films with Various Deposition Temperatures

The mechanical properties, such as nano-indentation hardness, texture coefficient, and water contact angle of titanium nitride (TiNx) films by rf-magnetron sputtering system have been investigated as a function of various deposition temperatures. The TiNx films grown over 360 degrees C exhibits an intense compressive stress compared with the films grown below 360 degrees C. The orientation of TiNx film was changed toward (111) direction at 360 degrees C due to increased ion bombardment which favors low surface energy at (111) orientation. The increase of substrate temperature increases the mobility of adatoms promoting closed packing structures in near thermodynamic equilibrium conditions. Thus, for high adatom mobility the TiNx films expected to grow along the (111) orientation corresponding to that with the lowest surface free energy. On the other hand, for low adatom mobility the preferred orientation is the (200) in which the highest number of atoms per unit area can be incorporated at low energy sites. The mechanical properties of TiNx films grown at a pure N-2 atmosphere strongly dependent on the Ts. The highest hardness and the smallest friction coefficient of 26 GPa and mu = 0.13, respectively were in a TiNx film deposited at 400 degrees C. This film was found to be accompanied by a water repellent surface.