The migration of Si micro-clusters on the (001) surface, at about 1500K, was observed by means of electron microscopy. Such clusters always had an associated region which melted first during heating, because of its lower crystallinity as compared with the Si substrate. The Si atoms in this melted zone were struck by electrons moving towards the anode, and were pushed - by the electron wind - in the same direction as the electrons. The Si micro-cluster, floating in the melted zone, also migrated towards the anode side; about 10 times as fast as the rate at which the Si atoms migrated in the opposite direction.

T.Doi, M.Ichikawa, S.Hosoki, K.Ninomiya: Applied Physics Letters, 1996, 68[11], 1493-4