Thermal stability and Sn diffusion in GeSn heterostructures

In this work, we address the thermal stability of GeSn alloys regarding strain relaxation and Sn diffusion. The two competing processes, i.e. dislocation formation and Sn diffusion, are investigated in different heterostructures to deduce the influence of the Ge buffer quality and anneal-ing temperature. Detailed characterization including Rutherford Backscattering Spectrometry (RBS), Second-ary Ion Mass Spectrometry (SIMS) and High Resolution X-Ray Diffraction (HR-XRD) are employed for charac-terization. From this, we conclude that thermal annealing is not the method of choice for strain relaxation of Sn based alloys. Thick and highly strained relaxed GeSn lay-ers can rather be obtained by in-situ growth