Effects of the Addition of Silane during Carbonization on the Epitaxy of 3C-SiC on Si

Abstract

By supplying another source of Si during the carbonization step, the Si out-diffusion was suppressed and the voids eliminated. Analysis was performed on both carbonized layers and ∼1 μm grown layers on Si(100) and (111) substrates to compare the results of carbonization with and without silane. Atomic force microscopy (AFM) images of the carbonized layer on Si(100) revealed that the pits present in the layer carbonized without silane could be suppressed by introducing a small amount of silane (Si/C = 0.05) during the carbonization step. The root-mean-square (rms) roughness of the (100) carbonized layer was reduced from 4.9 to 0.3 nm at this Si to C ratio. AFM images of the Si(111) samples were less conclusive. Scanning electron microscopy (SEM) images of the ∼1 μm 3C-SiC epitaxial layers revealed that carbonizing with silane (Si/C = 0.06) improved the 3C-SiC/Si interfaces of both the (100) and (111) samples; the voids at the interface were completely eliminated. SEM images and AFM analysis of the 3C-SiC epitaxial layers showed that the surfaces were smoother when silane was added. X-ray diffraction (XRD) results revealed that there is no significant improvement in the crystal quality of the grown layers. Nevertheless, the reduction in surface roughness is beneficial for device fabrication or subsequent heteroepitaxy, such as zinc blende GaN on 3C-SiC/Si(100).