Enhancement of the thermal stability of TiN_x capping layer on the nickel silicides

In this study, the effects of TiN_x capping layers on the thermal stability of nickel silicides have been investigated in a rapid thermal annealing (RTA) process. Various TiN_x films were deposited on the nickel film by different N₂ flow rates. It was found that the TiN_x capping layer could improve the thermal stability of nickel silicides and suppress silicide agglomeration. The TiN_x film deposited with higher N₂ flow rates had better thermal stability than those with lower N₂ flow rates. The corrosion behaviors of the TiN_x films deposited with various N₂ flow rates and nickel films in the H₂SO₄:H₂O₂ (4:1) solution were investigated. We found that the corrosion currents (I _corr) of the nickel and NiSi films were much higher than those of the TiN_x films, while the I_corr of the TiN_x films deposited with higher N₂ flow rates was much lower than that of the TiN_x films deposited with lower N₂ flow rates.