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

Abstract

AbstractThe 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, H2 and CH4 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 H2 concentration of 10% (H2/CH4 ratio of 40). Following the carbonization process, 3C‐SiC films were deposited from a CH3SiH3 single source or CH4 and SiH4 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.