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/ cm2 and 1 W/cm2, respectively. Deep photoluminescence around 0.8 eV and luminescence due to D3 dislocations at 0.94 eV were not observed under any excitation conditions.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)