Heteroepitaxial growth of cubic SiC on Si using very‐high‐frequency plasma at atmospheric pressure

The heteroepitaxial growth of cubic silicon carbide (3C‐SiC) on Si(001) at a substrate temperature of 800 °C was investigated using atmospheric‐pressure plasma excited by very‐high‐frequency (VHF) power. The carbonization process of the Si surface was first studied using plasma of He, H 2 and CH 4 mixtures to suppress the undesired influences of the large lattice mismatch between Si and 3C‐SiC. A (001)‐oriented 3C‐SiC layer, with thickness of approximately 3 nm and a root mean square roughness of 0.23 nm, was formed by supplying the optimum VHF power for a H 2 concentration of 10% (H 2 /CH 4 ratio of 40). Following the carbonization process, 3C‐SiC films were deposited from a CH 3 SiH 3 single source or CH 4 and SiH 4 dual sources by varying the atomic concentration ratio (C/Si). The crystal quality of the deposited films was characterized using infrared absorption spectroscopy, transmission electron microscopy and selected‐area electron diffraction. The results showed that increasing the C/Si ratio was essential to improve both the deposition rate and the crystal quality. The 3C‐SiC film deposited at C/Si = 10 exhibited the (001) 3C‐SiC growth epitaxially aligned to the Si matrix, although it included a high density of planar defects originating from twinned 3C‐SiC. Copyright © 2008 John Wiley & Sons, Ltd.