Grain-size and impurity effects in low-temperature deposition of TiN

Commercially deposited titanium nitride (TiN) thin films have been available during recent years. These TiN films possess high hardness and have good wear resistance; however, the deposition process typically requires a temperature of 500°C or higher. In many cases, due to substrate characteristics, a deposition temperature below 150°C is required in order to exploit TiN coating properties. The objective of this work is to demonstrate that ion beam assisted deposition (IBAD) makes it possible to deposit gold-color TiN films with good adhesion onto a variety of substrates including plastics at temperatures below 150°C. These films have physical and mechanical properties as good as those produced at high temperatures. Samples have also been examined by nanohardness techniques to accurately determine the hardness of the films and relate them to process parameters and crystal sizes. Our results indicate that, by controlling the grain size of TiN, it is possible to fabricate TiN coatings at room temperature with hardness as high as 25.5 ± 1 GPa.