Calculation of the electromigration wind force in Al alloys

The electromigration wind force in various Al alloys is calculated using a Green's-function method for the calculation of the electronic structure. The influence of the environment of the jumping atoms is studied in detail in the AI-Cu alloy. Alloys of Al with 3d and 4sp alloying elements are studied systematically in order to investigate the relation between the electronic states of the alloying atom and the wind force. The study also includes several other alloys, which have been used in the past in attempts to increase electromigration lifetime. It is shown that the wind force on an Al host atom can be changed considerably by the presence of an alloying atom at particular positions near the jump path. This could be an additional contribution to the well-known decelerating effect of some alloying elements on electromigration in Al. [S0163-1829(99)01112-1].