ELECTROMIGRATION OF METALLIC ISLANDS ON THE SI(001) SURFACE

The electromigration of metallic islands formed by vapor deposition on a Si(001)2 X 1 surface has been investigated with an ultrahigh-vacuum scanning electron microscope by heating the Si substrate at temperatu res higher than the melting points of the islands while passing a dire ct current through the Si substrate. The direction of the island migra tion depends on the type of metal. The speed is approximately proporti onal to the island radius and decreases exponentially with inverse tem perature. The activation energy for the migration of Au islands is 0.7 5 eV. The driving force of the island migration is discussed.