Mass transport due to momentum exchange between conducting electrons and diffusing metal atoms. Electromigration causes progressive damage to the metal conductors in an integrated circuit. It is characteristic of metals at very high current density and temperatures of 100C or more.
Mass transoport occurs via the Einstein relation J=DFC/kT where F is the driving force for the transoport. For electromigraiton F is z*epj and z* is an electromigration parameter relating the momentum exchange and z is the charge of the "diffusing" species.