Effect of DC input power and nitrogen ratio on the deposition of Ti1 − xAlxN thin films using high power impulse magnetron sputtering technique

Abstract Ti 1 − x Al x N thin films with x varying from 0.72 to 0.86 were deposited using a high power impulse magnetron sputtering (HiPIMS) method in this research. The current-voltage characteristics of the Ti 30 Al 70 target was first investigated to determine the HiPIMS parameters for film deposition. The microstructure and hardness of the resulting films grown under different target powers and different N 2 /Ar flux ratios have been studied. It was found that the dual phases of cubic-Ti 1 − x Al x N and wurtzite-AlN co-exist in the resulting films while the grain sizes of wurtzite-AlN are all smaller than that of the cubic-Ti 1 − x Al x N. The deposition rate, ranging from 4 to 9 nm/min, decreases with increasing N 2 /Ar flux ratio or decreasing target power. N/(Al + Ti) ratio, varying between 0.5 and 1.3, was found to increase with increasing N 2 /Ar ratio. Films having the highest hardness of 22.3 GPa was obtained when the duty cycle was 3%, the power was 1.8 kW, and the N 2 /Ar flux ratio was 0.46. The hardness exhibits a strong dependence to the N/(Al + Ti) ratio.