Influence of the silicon overlayer thickness of SOI unibond substrates on β-SIC heteroepitaxy

The present paper describes the epitaxial growth of high quality 3C–SiC on the top of silicon on insulator (SOI) UNIBOND substrates, to achieve an electrical insulation. The process was performed at 1200°C using methylsilane as the precursor gas. The crystal quality was proved using X-ray analysis. The FWHM of the [200] rocking curve reflex was determined to 0.31° using a 200 nm thick SOL. A serial resistance of the SiO2 layer of 2.5·1012 Ω mm2 was obtained at RT which proofs the insulation to the substrate. A technique based on sacrificial oxidation was applied to thin the silicon overlayer (SOL). SOLs between 15 and 200 nm could be prepared. The influence on the structural properties of the SiC film was studied using X-ray, AFM and TEM measurements. It was found that structural properties are dependent on the deposition process and on the SOL thickness. High quality SiC can be grown on SOLs thicker than 50 nm. Possibilities for the growth of highest quality SiC even on much thinner SOLs are discussed.