Fourth power law of time dependence of Si adsorbate diffusion on a Si(001) surface

Diffusion of Si adsorbates deposited on a Si(001) surface is investigated by reflection electron microscopy. At temperatures up to about 600 °C, the diffused length x of the adsorbates is proportional to t1/4 before the critical time tc, where t is the heating time. At ttc, the diffused length x is proportional to t1/2, where x is determined by thermal diffusion of the adsorbates.