Variation of the nanostructural feature of nc-SiC:H thin films with post-deposition thermal annealing

Highlight
• Hydrogenated amorphous SiC thin films were deposited by PECVD.
• The nanostructural evolution was investigated in term of annealing temperature.
• Nc- SiC sizes ranging from ~ 2 to ~ 5 nm were produced by post-deposition annealing.
• Variation of the optical band gap was related with the SiC nanocrystallites.
• The nanostructural and chemical features were related to DSC results of a-SiC:H.

Amorphous silicon carbide (a-SiC) thin films were prepared by plasma enhanced chemical vapor deposition. The films were post-deposition annealed in a N2-H2 atmosphere at temperatures ranging from 700 to 1300 °C. As the annealing temperature was increased from 1000 to 1300 °C, nanocrystalline silicon carbide (nc-SiC) formed and the mean crystallite size varied from ~ 2 to ~ 5 nm. The thermal energy at high annealing temperatures broke the Si-H and C-H bonds, and rearranged the amorphous network to generate local crystalline states, resulting in the formation of nc-SiC. The photoluminescence (PL) peaks varied in the wavelength range of ~ 425 to ~ 470 nm with annealing temperature. The optical band gap of the films has been associated to the maximum PL peak position and estimated to range from ~ 2.92 to ~ 2.64 eV.