Growth and photoluminescence of high quality SiGeC random alloys on silicon substrates

We report chemical vapor deposition growth of SiGeC layers on ^100& Si substrates. At the growth temperature of 550 °C, the C concentration as high as 2% can be incorporated into SiGe ~Ge content ; 25%! to form single crystalline random alloys by using low flow of methylsilane ~0.25 sccm! as a C precursor added in a dichlorosilane and germane mixture. For intermediate methylsilane flow ~0.5 sccm – 1.5 sccm!, the Fourier transform infrared spectroscopy ~FTIR! absorption spectra indicate the growth of amorphous layers. For the layers with high flow of methylsilane ~12 sccm!, there are silicon-carbide-like peaks in the FTIR spectra, indicating silicon carbide precipitation. The films were also characterized by x-ray diffraction, high resolution transmission electron microscopy, secondary ion mass spectroscopy, and Rutherford backscattering spectroscopy to confirm crystallinity and constituent fractions. The defect-free band-edge photoluminescence at both 30 K and 77 K was observed in Si/SiGeC/Si quantum wells, even at power densities as low as 0.5 W/ cm and 1 W/cm, respectively. Deep photoluminescence around 0.8 eV and luminescence due to D3 dislocations at 0.94 eV were not observed under any excitation conditions. © 1996 American Institute of Physics. @S0021-8979~96!02217-7#