Effect of filament temperature on properties of hot wire CVD deposited nc-3C-SiC films from SiH4–C2H2–H2 mixture

Abstract

In this study, nanocrystalline cubic SiC (nc-3C-SiC) thin films were deposited from SiH4 and C2H2 gas mixture by hot wire chemical vapour deposition technique. The influence of tungsten filament temperature TF on the film’s structural and optical properties was investigated. The deposited thin films were characterised by a variety of techniques, including Fourier transform infrared spectroscopy, Raman scattering, X-ray diffraction and ultraviolet–visible–near infrared spectroscopy. It was found that the film’s structure changed from microcrystalline Si into nc-3C-SiC with increasing TF from 1600 to 2000°C. An increase in TF enhanced the crystallinity of SiC films, and the optical band gap increased from 1·6 to 2·5 eV. Comparing with CH4, C2H2 could be easily decomposed at proper TF. Consequently, the carbon incorporation rate into the SiC film was intensively increased.