RECONSTRUCTION AND GROWTH OF AG ON THE SI(111)-ROOT-3X-ROOT-3-AG SURFACE AT LOW TEMPERATURE

摘要

Surface reconstruction structures and epitaxial growth of Ag on the Si(111)-root 3X root 3-Ag structure at low temperature (160-K order) have been investigated by reflection high-energy electron diffraction (RHEED). When Ag was deposited on a root 3X root 3-Ag surface at 160 K, reconstruction structures root 21X root 21 and 6X6 were observed in addition to the root 3X root 3 structures. The root 3X root 3 and root 21X root 21 structures were observed for a thickness range between 0.19 and 2.6 ML, and the 6X6 structures appeared and coexisted with the root 3X root 3 and root 21X root 21 structure between 0.7 and 1.7 ML. From RHEED patterns analysis, a 6X6 model was proposed. Beyond Ag growth of 3 ML, three-dimensional (3D) Ag islands were formed at the temperature range from 160 K to RT. These results imply that the mean free path of Ag atoms on the root 3X root 3-Ag surface is large enough even at 160 K that 2D nuclei cannot be formed on the terrace in spite of decreasing substrate temperature. [References: 21]