Epitaxial growth of Sb thin film and chemical reaction of Sb-induced surface reconstruction on Si(1 1 3)3×2

Abstract

Antimony layers deposited on a Si(1 1 3)3×2 surface are investigated with low energy electron diffraction (LEED) and Auger electron spectroscopy (AES). No long-range order is obtained in the room temperature grown Sb layer. Post-growth annealing at about 100°C restores long-range order and produces two-domain sixfold symmetric hexagonal structure. The tilted angle between two domains is 33.6°, which corresponds to the angle between [ 7 ̄ 4 1] and [4 7 ̄ 1] direction on bulk-terminated Si(1 1 3) plane. Sb (MNN) and Si (LMM) AES peak-to-peak intensities as a function of Sb deposition time at 100°C indicate that the overlayer structure grows a layer-by-layer fashion on the Si(1 1 3) surface at least up to two full molecule layer. Simple overlayer structure model, which consists of Sb n ( n=1–4) molecules, is suggested. Depending on the substrate temperatures above 300°C and Sb coverages, the 1×1, 2×2, and 2×5 reconstructions are formed successively. Oxygen exposure shows quite different surface chemical reactivities depending on the surface structures. The 1×1 and 2×2 surfaces are strongly passivated, on the other hand, the 2×5 surface reacts with oxygen relatively well. The different chemical reactivity is explained by the existence of the Sb lone pairs and Si dangling bonds in the unit cells.