The Low Temperature Epitaxy of Strained GeSn Layers Using RTCVD System

Abstract: We have investigated the low temperature (LT) growth of GeSn–Ge–Si structures using rapid thermal chemical vapor deposition system utilizing Ge₂H₆ and SnCl₄ as the reactive precursors. Due to inappropriate phenomena, such as, Ge etch and Sn segregation, it was hard to achieve high quality GeSn epitaxy at the temperature > 350 °C. On the contrary, we found that the SnCl₄ promoted the reaction of Ge₂H₆ precursors in a certain process condition of LT, 240–360 °C. In return, we could perform the growth of GeSn epi layer with 7.7% of Sn and its remaining compressive strain of 71.7%. The surface propagated defects were increased with increasing the Sn content in the GeSn layer confirmed by TEM analysis. And we could calculate the activation energies at lower GeSn growth temperature regime using by Ge₂H₆ and SnCl₄ precursors about 0.43 eV. Graphical Abstract: [Figure not available: see fulltext.].