Thermal stability studies of tungsten nitride thin films

Superior mechanical properties, such as hardness of high level along with thermal stability are of great technological interests for cutting tools and other industrial applications. In this work, we present performance and stability of tungsten nitride (WN) film at a wide temperature range (RT – 600°C). WN films were deposited on silicon (100) substrates using reactive RF magnetron sputtering. The deposited samples were annealed at 200, 400 and 600°C for 2 h. Structural, electrical and mechanical properties of the films were analysed via X-ray diffraction, four-probe resistivity and nano-indentation test, respectively. XRD results show the formation of pure W2N crystalline phase. The change in microstructural parameters were investigated and found to be varying with annealing temperature. The electrical measurement result shows the decrease in resistivity with an increase in annealing temperature. Nano-indentation experiments reveal that the mechanical behaviour (hardness and elastic modulus) at different load are quite stable in the studied temperature range.