We have investigated the physical properties of Ti-Si-N films for future Cu metallization on ULSIs. Our Ti-Si-N films were found to be amorphous by X-ray diffraction measurements. Thermal stability of the amorphous structure was confirmed, even after annealing at 600°C for 30 minutes in an Ar ambient. The atomic composition of the film was identified as Ti:Si:N=1:0.6:1.6 by chemical analysis. The film stress was found to be tensile and 0.3GPa. The electrical resistivity was about 0.5m Ωcm at room temperature.
The effectiveness of the film as a diffusion barrier was evaluated by n+/p and p+/n junction leakage measurements. The junction depth was 0.2Ω m and the contact area was 300×80μ2. No degradation of leakage characteristics was observed for these diodes, even after annealing at 600°C for 30 minutes in an N2/H2 ambient.
These results demonstrate that amorphous Ti-Si-N barrier metal is a promising candidate for application in deep-submicron ULSIs.