Forming method of silicide film

1. A forming method of a silicide film comprising:

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 that has a surface from which a nitride film has previously been removed;

forming a titanium nitride film on said titanium film in accordance with a reactive sputtering process using a gas containing a nitrogen atom and the titanium target; and

performing a heat treatment to react said cobalt film with said silicon substrate, thereby accomplishing silicification.

2. The forming method of a silicide film according to claim 1 , wherein the nitride film on the surface of said titanium target that is previously removed is removed by sputtering said titanium target.

3. The forming method of a silicide film according to claim 1 , wherein said gas containing the nitrogen atom is a nitrogen gas.

4. The forming method of a silicide film according to claim 1 , wherein said forming the titanium nitride film is performed in a low temperature atmosphere such that the titanium nitride film contains titanium.

5. The forming method of a silicide film according to claim 1 , wherein said forming the titanium nitride film is performed under temperature conditions that a temperature of said silicon substrate is within a range of 50° C. to 100° C.

6. The forming method of a silicide film according to claim 1 , wherein said performing the heat treatment comprises:

a first annealing for changing said cobalt film on said diffusion layer to a cobalt monosilicide film; and

a second annealing for removing said titanium nitride film containing titanium and unreacted cobalt film, and then changing said cobalt monosilicide film to a cobalt disilicide film under higher temperature conditions than that of said first annealing.

7. The forming method of a silicide film according to claim 6 , wherein said forming the cobalt film to said first annealing are continuously performed in a same equipment.