Effects of electric field annealing on the interface diffusion of Cu/Ta/Si stacks

► The atom diffusion is accelerated by the electric field. ► The acceleration is enhanced with an increment of annealing temperature. ► It is resulted from the increase of the mobility of vacancies and atoms. In the present paper, the effects of electric field annealing on interface diffusion of Cu/Ta/Si stacks were studied by means of XRD, XPS and TEM. The barrier property of Ta films was evaluated based on the diffusion of Cu atoms. It was found that the external electric field accelerates the diffusion of Cu atoms through Cu/Ta/Si interfaces during annealing. With the increment of annealing temperature, the effect of the electric field upon the atomic diffusion becomes more significant. The mechanism of accelerated interface diffusion is suggested and the failure of Ta barrier layer is discussed based on the mobility of vacancies and Cu atoms inside Cu/Ta/Si stacks caused by the electric field.