Epitaxial CoSi2 films were grown on Si(1 0 0) substrates via direct solid-phase reaction between crystalline (0 0 2) textured Co films and the Si substrates. Rutherford backscattering/channeling spectrometry and high-resolution transmission electron microscopy were performed to evaluate the epitaxial quality of the CoSi2 films. A good channeling chi(min) value of 20% was measured For the CoSi2 films formed alter rapid thermal annealing at 850 degrees C, which is comparable to that of the CoSi2 films obtained by Ti-interlayer mediated epitaxy (TIME). Similar with TIME, the intermediate phase of Co2Si was skipped in this case. The concept of "thermodynamic barrier" has been employed to explain the improvement In the epitaxy of CoSi2 films compared with the reaction between amorphous Co films and Si substrates.