Growth and structural properties of step-graded, high Sn content GeSn layers on Ge
Description | |
Date | |
Authors | Aubin J., Hartmann J.M., Gassenq A., Rouviere J.L., Robin E., Delaye V., Cooper D., Mollard N., Reboud V., Calvo V. |
Year | 2017-0416 |
Source-Title | Semiconductor Science and Technology |
Affiliations | Univ. Grenoble Alpes, Grenoble, France, CEA, LETI, Minatec Campus, Grenoble, France, CEA-INAC, Univ. Grenoble Alpes, Grenoble, France |
Abstract | Two approaches have been compared for the low temperature epitaxy of thick, partially relaxed GeSn layers on top of Ge strain relaxed buffers. The benefit of using step-graded instead of constant composition layers when targeting really high Sn contents (16%, here) was conclusively demonstrated. Digermane (Ge2H6) and tin-tetrachloride (SnCl4) were used as Ge and Sn precursors, respectively. The growth pressure (100 Torr) and the F(Ge2H6)/F(SnCl4) mass-flow ratio being constant, it was through a temperature lowering that the Sn concentration in the graded structure was increased. X-ray diffraction, atomic force microscopy and transmission electron microscopy were used to gain access to the Sn concentration, the strain state, the surface morphology and thicknesses of the heterostructures. Using a step-graded approach allowed us to gradually relax the strain in the GeSn layers. It helped us obtain high crystalline quality and avoid Sn segregation/precipitation for high Sn contents. © 2017 IOP Publishing Ltd. |
Author-Keywords | atomic force microscopy, chemical vapor deposition processes, GeSn alloys, high resolution x-ray diffraction, semiconducting Ge |
Index-Keywords | Atomic force microscopy, Chemical vapor deposition, Germanium, High resolution transmission electron microscopy, Temperature, Transmission electron microscopy, Vapor deposition, X ray diffraction, Chemical vapor deposition process, Constant composition layers, GeSn alloys, Graded structure, High resolution X ray diffraction, High-crystalline quality, Low temperature epitaxies, Strain relaxed buffers, Tin |
ISSN | 2681242 |
Link | Link |