Growth of SiC nanoparticles in C/Si multilayers using annealing

Conventional nanoparticles were directly synthesized in single film by PVD or CVD process. In this paper, we proposed a novel approach to the growth of SiC nano-particles (np-SiC) by thermal annealing of C/Si multilayers deposited on single crystalline Si (100) substrates using ion beam sputtering system (IBS). The deposition of C/Si multilayers was performed at room temperature under ultra high vacuum at a base pressure of 10^-7-10^-8Pa and then post high vacuum annealing at 500- 900 °C at 10^-4Pa. The np-SiC in C/Si multilayers were examined by scanning electron microscope (SEM) for particle characterization, and grazing incidence X-ray diffractometer (GIXRD) for phase identification. The size distribution and geometrical arrangement of np-SiC strongly depend on the thermal annealing temperature. The higher the annealing temperature, the more the nanoparticle size and density. Owing to the high surface energy, SiC nanoparticles, instead of film, are preferred to form on the surface in order to reduce the surface energy of film during annealing. After vacuum annealing at 900 °C for 1.0 hr, the size and density of np-SiC are about 300-600 nm in diameter and 1.37 × 10⁸cm^-2, respectively. The growth of np-SiC is attributed to the thermal annealing induced surface energy variation between Si and C reaction in thin C/Si multilayers.