OPTICAL STUDIES ON SILICON CARBIDE WIDE BAND GAP MATERIALS AND STRUCTURE

Abstract

Silicon carbide is becoming a technologically important material for the fabrication of blue light-emitting diodes (LEDs) and devices working in high temperature , high power, high frequency and high radiation environments because of its special properties such as wide bandgap, high electric breakdown high thermal conductivity and excellent thermal and chemical stability. In this paper, a combined structural and optical assessment of cubic(3C-) SiC thin films grown on Si (100) substrates by chemical vapor deposition(CVD) is presented. The CVD growth was performed at both atmospheric and low (100 Torr) pressure, using a vertical reactor. The CVD-grown 3C-SiC films with different growth time were characterized by Raman Scattering. Lorentzian curve fitting was used to obtain phonon structure parameters, i.e. intensity, full width at half maximum(FWHM). A series of epitaxial 4H-SiC thin films grown by low pressure chemical vapor deposition (LPCVD) were characterized by Raman scattering and FTIR .The epilayers were grown on heavily doped n-type 4H-SiC substrates using different gas compositions. FTIR reflectivity spectra indicated improvement in the film quality over that of the substrate and atmospheric pressure-grown epilayers. Rotating Raman scattering was performed on these samples.