Surfactant-mediated epitaxy of Ge on partially Ga-terminated Si(111) surfaces

Abstract

Surfactant-mediated heteroepitaxy of Ge on Si(111) with Ga as surfactant has been studied using a recently developed apparatus of scanning reflection electron microscopy combined with scanning tunneling microscopy. It has been found that Ge film formation of 4.3 ML thickness on a Ga-terminated √3×√3 surface results in two-dimensional island growth in contrast with pseudomorphic growth on 7×7 surface. Irregular growth of Ge clusters along the lower sides of atomic step edges also takes place on the √3×√3 surface at an elevated substrate temperature. Ge film was also grown on partially Ga-terminated Si(111) with both Ga-adsorbed √3×√3 and Ga-desorbed 7×7 reconstruction areas on the surface. It has been found that self-organized Ge clustering occurs along the Ga-desorbed 7×7 area with stripe shape.