Growth and Characterization of High Quality Si_l-x-yGe_xC_y Alloy Grown by Ultra-High Vacuum Chemical Vapor Deposition

High quality Si_l-x-yGe_xC_y alloy with 2.2% C is grown at a relatively high temperature (760°C) on Si(100) using ultra-high vacuum/chemical vapor deposition (UHV/CVD) system. The samples are investigated with high resolution cross-sectional transmission electron microscope and x-ray diffraction. Compared with Si_l-x-yGe_x alloys, Si_l-x-yGe_xC_y alloys with small amounts of C have much less strain and larger critical layer thickness. The quality of interface is also improved. Relatively flat growing profiles of the film are confirmed by secondary ion mass spectroscopy. Fourier transform infrared spectroscopy is also used to testify that the carbon atoms are on the substitutional sites. It is proved that the UHV/CVD system is an efficient method of growing Si_l-x-yGe_xC_y alloys.