Control of Co flux through ternary compound for the formation of epitaxial CoSi2 using Co/Ti/Si system

초록

A ternary compound of Co<inf>3</inf>Ti<inf>2</inf>Si is suggested as reaction barrier for the formation of epitaxial CoSi<inf>2</inf> in the Co/Ti/Si system. It has a role to control Co diffusion to the Si substrate, followed by formation of CoSi<inf>2</inf>. After Co<inf>3</inf>Ti<inf>2</inf>Si was formed, CoO and Ti oxide were formed at surface, depending on Ti thickness. In the case of Ti oxide being at surface, the outdiffusion of Ti in ternary compound was accelerated. Then, the decomposition of Co<inf>3</inf>Ti<inf>2</inf>Si occurred by reaction with Ti oxide, resulting in uniform epitaxial CoSi<inf>2</inf>. However, in the case of CoO being at surface, the Ti outdiffusion was suppressed, followed by thermally decomposition of Co<inf>3</inf>Ti<inf>2</inf>Si. This caused nonuniform Co supply to form nonuniform CoSi<inf>2</inf>. © 1996 American Institute of Physics.