Application of Ultraviolet Diffuse Reflectance in the Study of Silicide Films

Abstract

The use of surface reflectivity techniques as a means of monitoring silicide films grown using rapid thermal annealing has been examined in the present study. Reflectivity changes were correlated with the conventional sheet resistance measurement on silicide films. The g‐line reflectivity of Ti and Co silicides is observed to be sensitive to the growth conditions as well as to substrate doping conditions. The measured reflectivity changes seem to indicate modifications in silicide surface morphology. Further, a correlation is found between surface modifications and crystal structure changes during film growth under first silicidation anneal. A subsequent higher temperature second anneal does not modify the surface of the silicide films. This observation indicates that the technique could be useful for examining, post facto the thermal history of the fully processed films. At high first anneal temperatures (>900°C) the dynamics of film surface evolution change significantly, as indicated by significant changes in reflectivity behavior. The diffuse reflectance technique is more sensitive in monitoring silicide process than the conventional sheet resistance technique, and can be used as a rapid in‐line process monitoring and analysis tool for examining the silicide process.