Low-temperature photoluminescence studies of chemical-vapor-deposition-grown 3C-SiC on Si

Publisher Website
Google Scholar
Abstract
26 cubic SiC (3C‐Sic) films grown on (100) Si by way of chemical vapor deposition (CVD) with SiC film thicknesses ranging from 600 Å to 25 μm have been studied by photoluminescence at 2 K. The ‘‘defect‐related’’ W band near 2.15 eV appears in very thin‐film samples. The G band near 1.90–1.92 eV and its phonon side bands G1 and G2 are believed to be related to dislocations and extended defects. The ratio ρ of the intensities of the G band and the strongest nitrogen‐bound exciton (N‐BE) TO(X) line may be used as a figure of merit for crystalline perfection in CVD 3C‐SiC films. General formulas for the band‐gap shift due to an axial stress, including three special cases—hydrostatic pressure and uniaxial and biaxial stress—are derived and applied to the CVD 3C‐SiC/Si system. An experimental relationship of stress in these epitaxial films of 3C‐SiC as a function of depth is obtained. It is shown that a 1–3 μm transition layer greatly reduces the interface misfit strain. For films thicker than 3 μm the film stress decreases slightly with increase of film thickness. The effects of biaxial stress on the relative intensities of N‐BE lines are experimentally studied. It is reported that biaxial stress in the SiC/Si system depresses the intensity of the no‐phonon line as well as the TA, LA, and LO phonon transitions of the N‐BE spectrum.