Investigation of the Growth of Si-Ge-Sn Pseudomorphic Layers on 200 mm Ge Virtual Substrates: Impact of Growth Pressure, HCl and Si2H6 Flows

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We have quantified the impact of various process parameters on the growth of thin, pseudomorphic SiyGe1-x-ySnx layers on 2.5 µm Ge buffers (themselves on Si(001) substrates). For GeSn layers, we found that 100 Torr was appropriate for the growth of high crystalline quality layers. The impact of the HCl mass-flow on the growth kinetics of thin Ge1-xSnx layers was also evaluated. Adding HCl retained Ge in the gaseous phase, resulting at 325°C in a growth rate decrease and a Sn content increase. Moreover, the growth of Ge1-xSnx was shown to be selective against SiO2 and SiN-covered Si substrates, even without HCl. Finally, various Si2H6 flows were added to the gas mixture to grow pseudomorphic SiGeSn layers. The quality of these layers was assessed by X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF) and atomic force microscopy (AFM).