Thermal relaxation of isolated silicon pyramids on the Si(100)2 x 1 surface

Silicon mounds fabricated on the Si(1 0 0)2 x 1 surface by a tip of a scanning tunneling microscope (STM) have been observed by STM at substrate temperature of 770 K. The shape of the mound is a quadrangular pyramid with facets of regular array of steps with double layer height. For all the step, the dimer rows are perpendicular to the step edges, so called the D-B step. Just after the fabrication, the pyramid begins to decay immediately layer-by-layer. During decay, the D-B steps move scarcely, but only the S-B steps at the bottom layer move due to attachment and detachment of atoms which are detached from the upper layers. For a single layer mound, the aspect ratio of the mound oscillates between about 2.5 and 1.5. (C) 2001 Elsevier Science B.V. All rights reserved.