Thermal Silicidation of Ni/SiGe and Characterization of Resulting Silicide Films Using Raman Spectroscopy and X-ray Diffraction

Thermal silicidation characteristics of Ni/Si1-xGex with various Ge content was studied under different annealing temperatures in the range of 225oC ~ 400oC in N2 ambient. TiN capped Ni/Si1-xGex/Si/SiO2/Si wafers with x values in the range of 0.15 and 0.30 in 0.05 intervals were used. Thermal silicide formation was performed in a stacked hotplate-based annealing system designed for 300mm wafers. For silicide characterization, measurements of spectral reflectance, sheet resistance, Raman spectra as well as X-ray diffraction curves were performed to investigate optical properties, electrical properties, crystallographic phases and reaction mechanisms. Multiwavelingth micro-Raman spectroscopy was found to be very promising as a non-contact, in-line silicidation process monitoring technique. We have studied effects of Ge content and annealing temperature dependence on the electrical and crystallographic properties of the resulting thermal silicides (nickel germanosilicides).