Thickness dependence of C-54 TiSi2 phase formation in TiN/Ti/Si(100) thin film structures annealed in nitrogen ambient

One of the most used metallization schemes on silicon is the ${\mathrm{TiN/TiSi}}_{\mathrm{2}}\mathrm{/Si}$ structure, since it has taken advantage of good electrical contact between Si and ${\mathrm{TiSi}}_{\mathrm{2}}$ and the property as a diffusion barrier of TiN. In the present study, this structure has been realized by sputter depositing different layers of TiN/Ti onto silicon (100) substrate and annealing them in nitrogen ambient at different temperatures. Transmission electron microscopy as well as grazing incidence x-ray diffraction have been employed to study the morphology and the crystallographic properties of the formed layers. Initial stage of the C-49 ${\mathrm{TiSi}}_{\mathrm{2}}$ formation has been investigated at 590 $°$ C and complete formation of C-54 ${\mathrm{TiSi}}_{\mathrm{2}}$ phase observed at 710 $°$ C for higher thickness samples. Our attention has been focused on the ${\mathrm{TiN/TiSi}}_{\mathrm{2}}\mathrm{/Si}$ structures obtained after annealing the deposited films at 710 and 850 °C. We demonstrate that at the annealing temperature of 850 °C as the thickness of the TiN/Ti deposited films is decreased from 600/560 to 175/30 Å, the formation of ${\mathrm{TiSi}}_{\mathrm{2}}$ (C-54) phase is almost inhibited due to a faster consumption of Ti in the formation of TiN.