Influence of In-Situ Annealing of Si-Rich Silicon Carbide Thin Films

Si-rich Silicon carbide thin films have grown popularity in the past decade for various opto-electronic applications. Post processing of these thin films at temperature higher than 1000oC usually lead to phase transformations to form Si nanoclusters embedded in amorphous SiC deposited by sputtering on thin films. However, the processing technique is crucial to avoid contaminants, and obtain good quality films. Therefore, a novel in-situ annealing approach within the deposition chamber is carried out at temperatures lower than usual. The influence of in-situ annealing on the material property is meticulously studied by means of Spectroscopic Ellipsometry (SE), Diffused Reflectance Spectroscopy (DRS), and Fourier Transform Infrared Spectroscopy (FTIR). In SE, the spectra are fitted using various models; the refractive index values confirm the Si-richness of the film. The band gap (2.5 to 1.5 eV) is extracted from UV spectra using Tauc plot, which confirms the coexistence of the multiphase structure with the possibility of having Si-NC with different dimensions. The results obtained are promising for optoelectronic device applications.