Epitaxial growth of CoSi2 film by Co/a-Si/Ti/Si(100) multilayer solid state reaction

Epitaxial growth of CoSi2 by solid state reaction of Co/a-Si/Ti/Si(100) is investigated. A Ti/a-Si composite interlayer is used to modify the diffusion barrier and influence the epitaxial growth process. The epitaxial quality of the CoSi2 is improved compared to the film grown by Co/Ti/Si reaction. A multielement amorphous layer is formed by a solid-state amorphization reaction at the initial stage of the multilayer reaction. This layer acts as a diffusion barrier, which controls the atomic interdiffusion of Co and Si while limiting the supply of Co atoms. CoSi2 grows as the first phase and the growth interface of the epitaxial CoSi2 is at both the CoSi2/Si and CoSi2/CoSi interfaces. Investigation of the growth kinetics shows that the activation energy of CoSi2 formation is larger than that without an amorphous Si layer.