Epitaxial growth of GeSn layers on (001), (110), and (111) Si and Ge substrates

We have examined the epitaxial growth of Ge1-Snx on Ge(001), Ge(110), Ge(111), and Si(110) substrates and have investigated the crystalline properties of the epitaxial layers. We found that the Sn incorporation into Ge epitaxial layer effectively suppress the formation of stacking fault and twin growth in low temperature molecular beam epitaxy. We also found the strain relaxation of Ge1-Snx layers strongly depends on the residual strain which is dominated on not only the Sn content but also the substrate orientation. We demonstrate that Ge1-x-ySixSny epitaxial layer lattice-matching to Ge substrate exhibits the high thermal stability thanks to small misfit strain to substrate.