A manufacturing method of a semiconductor device includes forming a cobalt film on a silicon substrate on which a diffusion layer is formed, forming a titanium film on the cobalt film using a titanium target having a surface from which a nitride film has previously been removed, forming a titanium nitride film containing titanium on the cobalt film by a reactive sputtering process using a nitrogen gas and the titanium target, and performing an annealing to react the cobalt film with the silicon substrate, thereby accomplishing silicification.