Initial reactions and silicide formation of titanium on silicon studied by Raman spectroscopy

Raman spectroscopy is used to study the initial reactions and silicide formation of evaporated and sputtered Ti on Si(100) substrates. The annealings were performed in a vacuum rapid isothermal annealing system or in a UHV chamber. Raman spectra were obtained after various processing stages or in situ in the UHV system. The results indicate that Si interdiffusion precedes the formation of crystalline silicides. It is suggested that the Si is incorporated in the Ti film, possibly leading to a disordered intermixing and also agglomerates near grain boundaries. The formation of the initial phase is limited by nucleation, and the phase exhibits a Raman spectrum distinct from the final phase presumed to be TiSi₂ which forms after annealing to greater than 700 °C.