Phases transformation in Ti(Ta)-Ni(Co)-Si-N systems

摘要

Investigations of the Ti-Co, Ti-Ni and Ta-Ni thin films produced by magnetron co-sputtering and electron beam co-evaporation on Si substrates heated to 700-800℃ in nitrogen ambient with and without buffer layers are described. The TEM data show clear phase separation of TaN and NiSi_2 for the Ta-Ni film deposited in a high N_2 pressure ambient. Deposition at lower N_2 pressure led to the formation of a mixed Ni-Ta-Si layer. The phase separation effect was absent for Ni-Ti films at high N_2 pressure. The presence of buffer layers strongly affected the surface diffusion reactions in the Co-Ti-Si system. Formation of Ti-(O) or CoSi_x amorphous layers at the Si surface prevented the interdiffusion of Si and Co, such that even pure Co or Co_2Si layers could be formed.