Heteroepitaxial Si _1-x-yGe _xC _y layer growth on (100)Si by atmospheric pressure chemical vapor deposition

Thin heteroepitaxial films of Si _1-x-yGe _xC _y have been grown on (100)Si substrates using atmospheric pressure chemical vapor deposition at 550 and 700°C. The crystallinity, composition and microstructure of the SiGeC films were characterized using Rutherford backscattering spectrometry (ion channeling), secondary-ion-mass-spectrometry and cross-sectional transmission electron microscopy. SiGeC films with up to 2% C were grown at 700°C with good crystallinity and very few interfacial defects, while misfit dislocations at the SiGe/Si interface were observed for SiGe films grown under the same conditions. This difference indicates that the presence of carbon in the SiGe matrix increases the critical thickness of the grown layers. SiGeC thin films (>110 nm) with up to 3.5% C were grown at 550°C with good crystallinity. The crystallinity of the films grown at lower temperature (550°C) was less sensitive to the flow rate of the C source (C ₂H ₄), which enabled growth of single crystal SiGeC films with higher C content.