Growth mechanism of epitaxial CoSi2 on Si and reactive deposition epitaxy of double heteroepitaxial Si/CoSi2/Si

The growth mechanism of epitaxial CoSi2 was studied using Co/Ti/Si multilayer solid phase reaction. Results showed that phase formation was controlled by diffusion of Co through the growing CoSix, although at the early stage of CoSi2 growth the diffusion of Co could be controlled by a Ti layer. A reactive deposition technique was also evaluated by using a conventional magnetron sputtering system. Results showed that an epitaxial CoSi2 layer was formed by controlling the Co sputtering rate not to exceed the Co diffusion rate through CoSix. However, the surface of CoSi2 became rough when the deposition rate was much slower than the Co diffusion rate through CoSix. The roughness was caused by the formation of CoSi2 (111) facets at the interface between CoSi2 and the Si substrate. Si/CoSi2/Si double heteroepitaxial structures were fabricated when Si and Co were sequentially sputter-deposited on a Si (100) substrate.