Growth and characterization of SiGeSn pseudomorphic layers on 200 mm Ge virtual substrates

In this contribution, we report on the growth of pseudomorphic SiGeSn layers on 2.5 μm thick Ge virtual substrates on Si(001). A single wafer reduced pressure chemical vapor deposition reactor was used for the 100 Torr epitaxy of those layers, with digermane (Ge₂H₆), tin-tetrachloride (SnCl₄) and disilane (Si₂H₆) as precursors. Detailed analyses regarding the growth kinetics, layer composition and surface morphology as function of the growth temperature and Si₂H₆ flow are presented. As the temperature increases we have, for the same precursor flows, a Si content increase and a Sn content decrease. The activation energy associated with the exponential increase of the SiGeSn growth rate with the temperature, 9.5 kCal.mol⁻¹, is close to that of GeSn (10.6 kCal.mol⁻¹). Furthermore, we show that the addition of Si₂H₆ to the gaseous mixture results (besides the expected Si content increase) in a Sn content increase and a Ge content decrease. This study yields a better understanding of the growth of SiGeSn compound semiconductors. (paper)