Patent ID: 7172967

Claim:
A method of forming a cobalt silicide layer comprising: forming a nitride spacer on a sidewall of the gate structure; forming a source/drain regions at surface portions of the silicon substrate that are positioned at both sides of the gate structure; forming a gate structure including a gate oxide layer pattern and a polysilicon layer pattern on a silicon substrate; introducing a vaporized cobalt precursor having a formula Co 2 (CO) 6 (R 1 â€”Câ‰¡R 2 ), wherein R 1 is H or CH 3 , and R 2 is H, t-butyl, methyl or ethyl, onto the silicon substrate as a source gas to form a cobalt layer on the silicon substrate, wherein the vaporized cobalt precursor is physisorbed and chemisorbed on the silicon substrate and a purge gas is introduced to separate the silicon substrate thereby providing a cobalt layer on the silicon substrate; forming a titanium layer on the cobalt layer; and thermally treating the silicon substrate to react silicon with cobalt to form the cobalt silicide (CoSi 2 ) layer, wherein the method is repeatedly performed to provide a cobalt layer having a desired thickness on the silicon substrate.