Scanning tunnelling microscopy was used to investigate the surface morphology of Ar+ ion-bombarded Si(001) surfaces, as well as the very early stages of solid-phase epitaxy on such surfaces. The latter consisted of hillocks which were 1 to 2nm in diameter and 0.35 to 0.75nm in height. The onset of solid-phase epitaxy occurred at about 590C. At this temperature, a 2 x 2 structure, surrounded by amorphous regions, was partially observed on the terraces of the surface. During annealing at 590 to 620C, areas of 2 x 2 and c(4 x 4) reconstruction surrounded by amorphous regions developed. New models for the 2 x 2 and c(4 x 4) structures were proposed in which alternating arrangements of the buckled dimers, together with missing dimer defects, were proposed.

K.Uesugi, T.Yao, T.Sato, T.Sueyoshi, M.Iwatsuki: Applied Physics Letters, 1993, 62[14], 1600-2