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 T_F 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 T_F from 1600 to 2000°C. An increase in T_F 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 T_F. Consequently, the carbon incorporation rate into the SiC film was intensively increased.

Keywords:

• HWCVD
• Etching
• Filament temperature
• Thin film
• nc-3C-SiC
• C₂H₂

This work was performed with financial support from the Chinese National High Tech ‘863’ Program (grant no. 2006AA03Z219) and a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.