Experimental and numerical evaluations of adhesion strength and stress in TiN films deposited on ti-implanted aluminum

Titanium ions were implanted into aluminum substrates at 40kV prior to magnetron sputtering deposition of the Ti interlayer and TiN film using our custom-designed multifunctional ion implanter without breaking vacuum. An 82-nm-thick modified layer was formed between the TiN film and the substrate. The characteristics of the implanted samples were compared to those of TiN∕Al and TiN∕Ti∕Al samples that were not preimplanted. Based on our scratch tests, the critical loading Lc of the TiN∕Ti∕Ti-implanted Al sample was significantly improved compared to the unimplanted TiN∕Al and TiN∕Ti∕Al samples. Finite element analysis was conducted to simulate the scratch process to help reveal the stress distributions in the vicinity of the interlayer. The results show that the stress around the interface is largely reduced in the TiN∕Ti∕Ti-implanted Al sample. Consequently, the mechanical properties such as resistance to loadings are enhanced.