In this study NiSi were investigated using XRD (X-Ray diffraction) to observe silicides phase transition from the low sheet resistance phase to the high sheet resistance phase. In the analyzed Ni silicide samples, the transition was observed to occur at the formation temperatures greater than 650-700ºC, according to XRD measurements and sheet resistance measurements performed using the four point probe method (V/I). Agglomerates and precipitated formation on the obtained silicide films were also investigated using SEM (Scanning Electron Microscopy).