Atomic force microscopy, transmission electron microscopy, and electron energy-loss spectroscopy have been used to study the size, structure, and composition of Ge/Si(100) islands grown by molecular beam epitaxy at 700°C. It is found that the island evolution is qualitatively different than for growth at lower substrate temperatures. For growth at 1.4 ML/min, the composition is determined to be Si0.56Ge0.44 and appears to be independent of island size. A higher growth rate, 4.8 ML/min, kinetically stabilizes pure Ge pyramids prior to Si interdiffusion taking place. These pure Ge clusters are absent at the lower growth rate, demonstrating the influence of deposition rate on island evolution. This result indicates that deposition kinetics can control island composition and morphology without varying growth temperature and associated thermally activated processes.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)