Influence of surfactants in Ge and Si epitaxy on Si(001)

Epitaxial growth of heterolayers has in the past relied on optimization of growth conditions to overcome thermodynamic obstacles. When there is an intrinsic tendency of a heterolayer to either island or interdiffuse, a common strategy is to lower the growth temperature and increase the growth rate to reduce surface mobility. An alternative strategy is to introduce a surface-active species (surfactant) that modifies the growth mode without significant levels of incorporation. This paper discusses the application of As and Sb surfactants to the growth of Ge/Si(001) and Si/GeSi(001). Results from analysis by medium-energy ion scattering, x-ray photoemission, and ultraviolet photoemission are reported. By using a surfactant, island formation is suppressed in the growth of both Ge/Si(001) and Si/Ge/Si(001), resulting in thick, epitaxial films. © 1990 The American Physical Society.