Effect of Predeposited Ge on the Growth of SiC Films on Si(111) by SSMBE

SiC films were grown at substrate temperature of 900 ℃ by solid source molecular beam epitaxy (SSMBE) on Si(111) with different thicknesses (0, 0.2, 1 nm ) of Ge predeposited on Si prior to the epitaxy of SiC. The films were investigated with reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR). The results indicated that the quality of the film with Ge predeposition of 0.2 nm was the best. The surface of the sample was even and there were no voids observed. The Ge prdeposition of 0.2 nm suppressed the Si diffusion and decreased the void formation. For the sample without Ge predeposition, the roughness of the surface was larger and there were some voids and Si grains on the surface. For the sample with the Ge prdeposition of 1 nm, island growth mode of Ge caused the surface of SiC films rougher and the crystalline quality of SiC film worse and even induced the formation of the polycrystalline SiC film.