In this report Ni-silicide formation processes are described using LEED-Auger and a high resolution FE-scanning electron microscope. Eight monolayers (ML) of Ni atoms were deposited on the clean and hydrogen-terminated (H-terminated) Si(110) surfaces. Ni atoms reacted strongly with silicon atoms at room temperature on the bare Si(110). However, on the H-terminated Si(110) surface Ni atoms reacted gradually with Si atoms with increasing annealing temperature, and formed a uniform layer and flat silicide surface. In contrast, on the bare Si surface, the silicide formed non-uniform but precipitous islands along the [112] direction with elevating, temperatures.