Formation of CoSi2films by the reaction of ternary Co/Ti/Si system has been investigated. Ti and Co films were sequentially deposited on Si substrates by ion beam sputtering. It succeeded in the growth of epitaxial single‐crystalline CoSi2films on both Si(111) and Si(100) substrates through a multistep annealing process with temperatures from 550 to 900 °C in a nitrogen environment. A thin layer of TiN was formed on top of the epitaxial CoSi2. The values of Rutherford backscattering spectrometry/channeling minimum yield &khgr;minfor the epitaxial CoSi2films were in the range of 10%–14%. The epitaxial CoSi2grown on Si(111) was found to be composed of typeB.