TISI2 formation and mechanism through ultra-thin Al2O3 intermediation

In this paper, TiSi
₂
formation through ultra-thin Al
₂
O
₃
intermediation is experimentally demonstrated and the mechanism for solid-state phase reaction is studied. By the intermediation of ultra-thin buffer layer, a thinner layer of amorphous Ti-silicide was obtained under the same annealing condition. It's found that the Si atomic diffusion process is almost retarded by the buffering layer while Ti atoms can still diffuse into Si substrate through the oxygen exchange effect between TiO
₂
and Al
₂
O
₃
. Due to lack of nucleation centers in the Ti/Al
₂
O
₃
/Si system, only amorphous C49 phase TiSi
₂
was formed with a Ti-rich silicide phase formed at the top surface. In the normal Ti/Si system, however, C54 phase can be obtained at high temperature.