Phase formation in Ti (Ta)-Ni and Co-Ti films deposited on (00l)Si in a N2 ambient

The transmission electron microscopy data show clear phase separation into TaSi₂ and NiSi₂ for the Ta-Ni film deposited in a high N₂ pressure ambient and the beginning of phase separation in the Co-Ti film deposited at low N₂ pressure. Changing the ambient conditions led to the formation of ternary compound films. Formation of Ti-(0) or CoSi_x, amorphous layers at the Si surface prevented the interdiffusion of Si and Co, such that even pure Co or Co2Si layers could be formed. Silicide and nitride layers play key roles in sub-micron ultra-large scale integrated devices. The TiSh contact layers which were used originally have been replaced by CoSi₂ which has a higher thermal stability, lower resistivity and fewer problems in the self-aligned process. Deposition was performed by either e-beam co-evaporation or magnetron sputtering, with either a high or low partial pressure of nitrogen.