Nickel mono-silicide(NiSi) shows no increase of resistivity as the line width decreases below 0.15 μm . Furthermore, thin silicide can be made easily and restrain the redistribution of dopants, because NiSi in created through the reaction of one nickel atom and one silicon atom. Therefore, we investigated the deposition condition of Ni films, heat treatment condition and basic properties of NiSi films which are expected to be employed for sub-0.15 μm class devices. The nickel silicide film was deposited on the Si wafer by using a dc-magnetron sputter, then annealed at the temperature range of 150 1000 ? C . Surface roughness of each specimen was measured by using a SPM (scanning probe microscope). Microstructure and qualitative composition analysis were executed by a TEM-EDS(transmission electron microscope-energy dispersive x-ray spectroscope). Electrical properties of the materials at each annealing temperature were measured by a four-point probe. As the results of our study, we may conclude that; 1. SPM can be employed as a non-destructive process to monitor NiSi/NiSi 2 transformation. 2. For annealing temperature over 800 ? C , oxygen pressure Po 2 should be kept below 1.5×10 ?11 torr to avoid oxidation of residual Ni. 3. NiSi to NiSi 2 transformation temperature in our study was 700 ? C from the four-point probe measurement.