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.