Thermal stability of germanium-tin (GeSn) fins

Abstract

We investigate the thermal stability of germanium-tin (Ge1-xSnx) fins under rapid thermal annealing in N2 ambient. The Ge1-xSnx fins were formed on a GeSn-on-insulator substrate and were found to be less thermally stable than blanket Ge1-xSnx films. The morphology change and material quality of the annealed Ge1-xSnx fin are investigated using scanning electron microscopy, Raman spectroscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and electron energy loss spectroscopy. Obvious degradation of crystalline quality of the Ge0.96Sn0.04 fin was observed, and a thin Ge layer was formed on the SiO2 surface near the Ge0.96Sn0.04 fin region after 500 °C anneal. A model was proposed to explain the morphology change of the Ge0.96Sn0.04 fin.