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

Abstract

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~5nm. 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~470nm 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~2.64eV.