Metastable structure of Si(111) surface during homoepitaxial growth

Abstract

The rocking curves of reflection high-energy electron diffraction (RHEED) intensities are measured during the homoepitaxial growth of the silicon (111) surface at a substrate temperature of 560 K. During the molecular beam epitaxial (MBE) growth, the RHEED pattern consisted of diffuse and weak streaks of 5 × 5 and 7×7 structures. One-beam rocking curve is very similar to that of a Si(111)δ7 × 7 surface during silicon deposition at room temperature. Since RHEED intensities of near half order spots are rather stronger than other spots in the pattern of the growing surface at 560 K, the surface structure is different from the δ7 × 7 one, and 2 a ( a = 3.84 Å) periodicity remains on the surface. It is concluded that a new pyramidal cluster-like structure is formed on the 7 × 7 and/or 5 × 5 dimer-stacking-fault framework during growth.