Initial stage of InAs growth on Si(001) studied by high-resolution transmission electron microscopy

Abstract

The initial stage of InAs growth on Si (001) substrate was studied via high-resolution transmission electron microscopy analysis. InAs of thickness less than 1 monolayer grown by molecular beam epitaxy was found to form islands at the onset of the growth, i.e., it follows the Volmer-Weber growth mode. By the introduction of 60 degrees and 90 degrees dislocations, the misfit strain was relieved at the early growth stage for island size as small as 10 nm. The average distance between the 60 degrees dislocations is approximately 2 nm, indicating nearly complete strain relaxation. The shape evolution of individual islands reveals the transition from pyramidal shape with (111) facets for island diameters smaller than 15 nm to dome shape for island diameters larger than 20 nm. (c) 2005 American Institute of Physics.