Bias voltage influence on surface morphology of titanium nitride synthesized by dynamic nitrogen and titanium plasma immersion ion implantation and deposition

Titanium nitride films were prepared on silicon wafers employing dual titanium and nitrogen plasmas in an immersion configuration. The vacuum arc source provided the titanium plasma and the nitrogen plasma was sustained by hot filament glow discharge. A 30 μs implantation duration and 270 μs titanium arc duration were used in our plasma immersion ion implantation and deposition (PIII–D) process. The impact of the implantation voltages (8, 16 and 23 kV) on the film surface morphology was investigated using atomic force microscopy (AFM). The 8 kV sample shows a surface featuring small islands. The surface of the 16 kV sample is smoother. The cones are more abundant but they are smaller and uniformly distributed on the surface. On the surface of the 23 kV sample, the islands exhibit a directional ripple structure. The implantation voltage unequivocally alters the fabrication dynamics of the coatings, and the difference is believed to be due to the variation in the energy imparted to the substrate at different depths by the incident ions. Films with the optimal surface morphology thus require a suitable voltage process window in the PIII–D technique.