APPLICATION OF ULTRAVIOLET DIFFUSE-REFLECTANCE IN THE STUDY OF SILICIDE FILMS

The use of surface reflectivity techniques as a means of monitoring si licide films grown using rapid thermal annealing has been examined in the present study. Reflectivity changes were correlated with the conve ntional sheet resistance measurement on silicide films. The g-line ref lectivity of Ti and Co silicides is observed to be sensitive to the gr owth conditions as well as to substrate doping conditions. The measure d reflectivity changes seem to indicate modifications in silicide surf ace morphology. Further, a correlation is found between surface modifi cations and crystal structure changes during film growth under first s ilicidation anneal. A subsequent higher temperature second anneal does not modify the surface of the silicide films. This observation indica tes that the technique could be useful for examining, post facto the t hermal history of the fully processed films. At high first anneal temp eratures (>900 degrees C) the dynamics of film surface evolution chang e significantly, as indicated by significant changes in reflectivity b ehavior. The diffuse reflectance technique is more sensitive in monito ring silicide process than the conventional sheet resistance technique , and can be used as a rapid in-line process monitoring and analysis t ool for examining the silicide process.