The electromigration of liquid metal inclusions in Si

Abstract

The electromigration velocities of liquid metal inclusions in single-crystal Si were found to follow an Arrhenius relationship with temperature. The activation energies and preexponential factors of liquid metal inclusions of Pd, Au, Cu, Al, Ag, Ga, In, and Sn were measured. Liquid Sb inclusions did not electromigrate. Electromigration velocities were linearly proportional to the applied electric current. Inclusions of Pd, Au, and Cu which have relatively high work functions electromigrate towards the anode while inclusions of Al, Ag, Ga, In, and Sn which have relatively low work functions electromigrate toward the cathode. The relative order of electromigration velocities within the anode-directed group and within the cathode-directed group can be accounted for by setting the electromigration force proportional to the difference between the work function of the metal of the inclusions and an experimentally determined null-point work function and by considering the solubility of silicon in the inclusion.