Papers by Keyword: Si_1-xGe_x

Abstract: Micro Raman characterization has been used to determine the stress status of 3C-SiC epilayer grown on pseudomorphic-Si thin layer on Si_1-xGe_x/Si(001). The strain conditions of the Si_1-xGe_x films grown on Si(001) have been determined by the analysis of additional Silicon Raman peaks, which Raman shifts are related to the lattice parameter. Through the analysis of the Raman spectra, the correlation between the Si_1-xGe_x film, the crystal quality and the stress relaxation of the 3C-SiC as a function of the Germanium fraction (x), have been evaluated. The increase of Germanium fraction determines the reduction of the voids density located at the 3C-SiC/Si interface and the relaxation of the stress within the epilayer. Moreover, the 3C-SiC crystal quality, monitored by the Full Width at Half Maximum of the TO Raman mode, remains unchanged for any Germanium fraction values.

Abstract: In this work, Si, Ge element composition distribution in Ge /Si_1-xGe_x:C /Si substrate structure has been characterized and modified by planar scanning energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The Ge /Si_1-xGe_x:C /Si substrate samples are grown by chemical vapor deposition (CVD) method. The accuracy of EDS value can be improved by ~ 32%. And the modified EDS results indicate the Ge distribution in the Ge/Si_1-xGe_x:C/Si sub structure.

Abstract: We have investigated the oxidation behavior of epi-Si_0.7Ge_0.3 films in dry oxygen ambient. Epi- Si_0.7Ge_0.3 films about 500Å in thickness were deposited on (100) Si wafers by UHV-CVD system. Oxidation was carried out in a conventional tube furnace at 800 °C . In this study, it was found that Ge piles up at the oxide/substrate interface, forming a Ge-rich layer. Because of the large difference in the heat of formation between SiO₂(-730.4KJ/mol at 1000K) and GeO₂(-387.07 at 1000K) [1], the Si is to be more reactive than Ge to oxygen. The oxidation rate of SiGe in a dry oxygen environment is found to be essentially the same as that of pure Si.