Laser microscopy of $CoSi2$ formation reaction at the CoSi/Si interface

We have for the first time successfully observed the $CoSi2$ formation process at the CoSi/Si interface by using a laser microscope. From the analysis of the laser microscope images, it is shown that the $CoSi2$ formation reaction at the CoSi/Si interface in the thin Co-film/Si-substrate structures has the following characteristics. 1) The initial reaction rate is much larger than that of the later reaction stage. 2) It seems that the large initial reaction rate originates in a high density of local seed points. 3) The annealing time dependence of the phase ratio during the later reaction stages shows that the reaction is not diffusion controlled.