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

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 root 3x root 3 surface results in two-dimensional island growth in contrast with pseudomorphic growth on 7x7 surface. Irregular growth of Ge clusters along the lower sides of atomic step edges also takes place on the root 3x root 3 surface at an elevated substrate temperature. Ge film was also grown on partially Ga-terminated Si(lll) with both Ga-adsorbed root 3x root 3 and Ga-desorbed 7x7 reconstruction areas on the surface. It has been found that self-organized Ge clustering occurs along the Ga-desorbed 7x7 area with stripe shape. (C) 1996 American Institute of Physics.