Structural investigation of the Ag-Ni-Si silicide films formed at 850 degree C by RTA on Si(100) substrates

Ag-Ni-Si silicide films are prepared by deposition of Ag films with thicknesses of 13,5-66,5nm on the Ni base films of 11,5-66,5nm, on n-type Si(100) by thermal evaporation technique, followed by rapid thermal annealing at 850 degree C for 60 s. Structural characterization of all the Ag-Ni-Si films has been investigated using XRD, SEM, X-SEM and AFM. Our XRD analysis reveals that the NiSi, NiSi2, Ag3Si, Ag2Si silicide phases co-exist in the Ag-Ni-Si films of 343-264nm, whereas beyond 264nm, the structure gradually transform into Si-rich silicide phases. At 66nm, NiSi2, Ag3Si and Ag2Si phases completely disapper and all the phases are mixed, indicating thermal breakdown of the phases. AFM reveals the ridge-like structures with high mean roughness values of 36,47-48,14nm. Our sheet resistance measurements shows that with decreasing film thicknesses from 343 to 66nm, the sharp increase (2,653-41,35 Ω/□) in resistances of the films is generated by significant phase transformation and film agglomeration, and finally at ≤66nm by thermal breakdown of the mixed-Si-rich phases.