The driving force on Si adsorbates at a (001) surface was investigated by means of reflection electron microscopy. When the sample was heated by using a direct current, the migration length of the adsorbates was proportional to the square root of the heating time, up to a critical time. This indicated that the dominant force on the Si adsorbates changed from thermal diffusion to electromigration at the critical time.

T.Doi, M.Ichikawa, S.Hosoki: Applied Physics Letters, 1996, 69[4], 532-4