A method for fabricating epitaxial cobalt disilicide layers uses a cobalt-nitride thin film. Epitaxial cobalt disilicide (CoSi2) layers are fabricated using a cobalt-nitride thin film in a salicide process, wherein a silicide is formed on source/drain regions and a polysilicon gate electrode of a nanoscale MOS transistor. Epitaxial CoSi2 layers can be fabricated on source/drain regions and a gate electrode of a silicon substrate using a cobalt-nitride thin film, without the formation of an interlayer between a cobalt layer and the silicon substrate.