Growth defects in GeSn/Ge/Si(001) epitaxial layers grown by hot wire chemical vapor deposition of Ge with co-evaporation of Sn

We report on the investigation of the growth defect formation in the GeSn/Ge/Si(001) epitaxial layers grown by hot wire chemical vapor deposition of Ge with simultaneous co-evaporation of Sn from an effusion cell. The nucleation of α -Sn nanoinclusions in the course of the growth process was found to be the main mechanism of elastic strain relaxation in the Ge 1 - x Sn x epitaxial layers at x > 2.5 % as opposed to the misfit dislocation formation at the GeSn/Ge interfaces. Also, β -Sn nanoislands nucleating on the surface of the GeSn epitaxial layers with increased Sn concentration due to Sn segregation were identified by confocal Raman microscopy.