SYNCHROTRON-RADIATION CHARACTERIZATION OF METAL SILICIDE THIN-FILMS -SOME OBSERVATIONS

X-ray absorption fine structures (XAFS) investigations of platinum sil icide and nickel silicide thin films using synchrotron light sources a re reported. These films were prepared with ion sputtering of metal on a clean Si(100) wafer, followed by rapid thermal annealing. XAFS at t he Ni K-edge, Pt L-3,L-2 and M-3,M-2-edges and Si K, L-3,L-2-edge have been used to obtain information about the structure and bonding syste matics of these systems, It is shown that single phase PtSi film is fo rmed after annealing under modest conditions while Ni-Si films undergo several phase transformations from Ni-rich silicide to NiSi and ultim ately NiSi2 as annealing temperature increases. It is also shown that Si L-3,L-2-edge studies using total electron yield and fluorescence yi eld are ideally suited for non-invasive characterization pf silicide t hin films, since there exists a large chemical shift in threshold ener gy (similar to 4 eV) between the silicide and silicon oxide. The relev ance of this information to the refinement of the salicidation process is noted. (C) 1997 Elsevier Science S.A.