Nickel silicide formation on Si(110) and Si(100) substrate was investigated in this paper. It is confirmed that nickel monosilicide (NiSi) starts to form after 450°C annealing for Si(100) substrate, but a higher annealing temperature is required for NiSi formation on Si(110) substrate, which is demonstrated by X-ray diffraction (XRD) and Raman scattering spectroscopy. The higher formation temperature of NiSi is attributed to the larger Ni 2 Si grain size formed on Si(110) substrate. Ni silicided Schottky contacts on both Si(100) and Si(110) substrates were also fabricated for electrical characteristics evaluation. It clearly reveals that the rectifying characteristics of NiSi/n-Si(110) Schottky contacts is inferior to that of NiSi/n-Si(100) Schottky contacts, which is attributed to a lower Schottky barrier height and a rougher contact interface. The formation kinetics for nickel silicide on Si(110) substrate is also discussed in this paper.