Isothermal Heteroepitaxy of Ge1–x Sn x Structures for Electronic and Photonic Applications

Epitaxy of semiconductor-based quantum well structures is a challenging task since it requires precise control of the deposition at the submonolayer scale. In the case of Ge_1-x Sn _x alloys, the growth is particularly demanding since the lattice strain and the process temperature greatly impact the composition of the epitaxial layers. In this paper, the realization of high-quality pseudomorphic Ge_1-x Sn _x layers with Sn content ranging from 6 at. % up to 15 at. % using isothermal processes in an industry-compatible reduced-pressure chemical vapor deposition reactor is presented. The epitaxy of Ge_1-x Sn _x layers has been optimized for a standard process offering a high Sn concentration at a large process window. By varying the N₂ carrier gas flow, isothermal heterostructure designs suitable for quantum transport and spintronic devices are obtained.