Effect of Si/C flux ratio on the growth of 3C-SiC on Si(111) by SSMBE

Abstract

The effect of Si/C flux ratio on 3C-SiC grown on Si (111) by solid-source molecular beam epitaxy (SSMBE) is investigated by reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The results indicate that there is an optimized Si/C flux ratio (1.5:1). In this case, besides SiC streaks, a (3×3) surface reconstruction can be observed in RHEED and the full width at half maximum (FWHM) of the rocking curve is 1.1°. For the sample grown at lower Si/C flux ratio (1.1:1), there are spots as well as ring patterns of SiC observed in RHEED and the FWHM of the rocking curve is 2.1°. For the sample grown at higher Si/C flux ratio (2.3:1), the RHEED indicate that Si spots coexist with SiC spots and the result of the rocking curve shows the FWHM of 1.5°. AFM results show that the surface of the sample grown at the optimized Si/C flux ratio is even and there are voids on the surface of the others. The results of FTIR indicate that the quality of the sample with optimized Si/C flux ratio is best. The more voids and defects of the samples with lower and higher Si/C flux ratios induce larger stress than that of the sample grown at optimized Si/C flux ratio (1.5:1).