Study of phase separation in Ti-Co-N thin films on silicon substrate

The interaction between Si and thin films of Ti₇₃Co₂₇ and Ti₇₃Co₂₇-N during thermal annealing has been studied by SIMS, AES and XRD methods. It has been shown that in case of Ti₇₃Co₂₇ the CoSi₂ layer was not formed and the formation of ternary suicide compounds CoTiSi and Co₃Ti₂Si took place. At the same time in case of Ti₇₃Co₂₇-N the bottom layer CoSi₂ and the upper layer based on TiN were formed. The interaction behaviour has been found to depend on nitrogen concentration in initial film. For high amount of nitrogen the diffusion of Si atoms into upper layer and Si₃N₄ phase formation were observed. The possible variants of solid-phase interaction between silicon and the alloys containing intermetallic compounds and influence of nitrogen on this process are discussed.