Experimental tests and numerical simulation studies on nano-indentation of TiN film deposited on N+-implanted aluminum

Nitrogen was implanted into aluminum substrate prior to magnetron sputtering of TiN films to introduce a modified layer between the TiN film and Al substrate. In another sample, a Ti interlayer was produced on the untreated substrate by means of magnetron sputtering. From the load-displacement curves obtained by the nano-indentation tests, the ring-like cracks appeared at 38 mN on the TiN/N+-implanted aluminum sample, 25 mN on the TiN/Ti/aluminum sample, and 18 mN on the TiN/untreated aluminum sample. The finite element method (FEM) was used to analyze the stress distribution at the interface of the various samples. The decline in the film base tensile stress and shear stress revealed the advantages of the pre-implanted substrate. All the numerical simulation results are consistent with the increased loading capacity obtained from the load-displacement curves.