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° and 90° dislocations, the misfit strain was relieved at the early growth stage for island size as small as 10nm. The average distance between the 60° dislocations is approximately 2nm, 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 15nm to dome shape for island diameters larger than 20nm.