We have investigated the effect of an interfacial Ti layer on the mechanism of CoSi2 formation. The presence of this Ti intcrlayer shifts the completion of all the cobalt suicide reactions to higher temperatures, reduces the sensitivity of these reactions to the presence of the native oxide on silicon, and greatly modifies the morphology of the CoSi2/ < 100 > Si interface. The modification of the interface morphology arises from the formation of highly < 110 > oriented or < 100 > epitaxial CoSi2 and results in greater thermal stability of the disilicide.