Scanning Tunneling Microscopy Study of Low-Temperature Epitaxial Growth of Silicon on Si(111)-(7X7).

摘要

Scanning tunneling microscopy is used to investigate nucleation and growth phenomena in the molecular-beam epitaxial (MBE) growth of silicon on Si(111)-(7x7) from the submonolayer range up to a few monolayers. At room temperature small amorphous clusters from which grow in locally ordered arrays on the (7x7) lattice. Deposition at a higher substrate temperature produces triangular islands of epitaxial silicon which have preferred step propagation in the (112) direction. Preferred nucleation of Si islands is found to occur along boundaries between (7x7) superstructure translational domains of the substrate. The preferred nucleation which arises from defects in the epilayer accounts for the formation of a second epitaxial layer long before the first layer is completed. A variety of metastable reconstructions which differ from (7x7) are also found in the epitaxial islands and are discussed. Keywords: STM, Nucleation, Low temperature, Silicon, Defects, Crystal growth, Metalloids, Epitaxy, MBE, Reprints. (jg)