Annealing effects on the optical properties of silicon carbide (SiC) thin films / Siti Hafizah Abdul Rauf

Silicon carbide (SiC) thin films were initially deposited at 250 °C and deposition rates of 0.12 cm/s using a home-built HW-CVD system. Much attention has been given to SiC as the most mature of the wide-bandgap semiconductor having a variation of energy-gap between 2.0 eV and 7.0eV. In this experiment, SiC thin film was chosen to be annealed to improve its electronic properties via heat treatment. The change in the SiC thin film that affects the optical properties of the thin film is studied. In order to study the effects on the properties of the film, the SiC thin film was annealed at elevated temperatures between 100 °C to 400 °C. Studies were done through characterizations using ultraviolet-visible spectra, X-ray diffraction spectra, and Raman spectroscopy. It was found that annealing has affected the properties of the film. The optical bandgap of the films was increased from 1.77 eV to 2.71 eV. The refractive index was also increased from 2.14 to 2.25 and the film thickness was reduced from 133.56 nm to 119.38 nm. Raman spectroscopy showed the variation in the intensity of the film and showed that the films were amorphous even after it was annealed but there is a variation in the intensity of the film composition. Analysis of the X-ray diffraction spectra of the thin film confirms that the thin film is amorphous silicon carbide (a-SiC).