Reaction of carbon and silicon at high temperature deposition

In order to study the reaction mechanism of in- situ formation of silicon carbide (SiC), the carbon was deposited on the crystalline silicon (c-SiC) substrate at high temperature of 400 - 600 degC using ultra-high-vacuum ion beam sputtering. X-ray diffraction, Raman spectra, Auger electron spectroscopy and high resolution scanning electron microscopy (SEM) with the attached dispersive X-ray (EDX) detector were used to examine the effect of substrate temperature on the reaction mechanism. Amorphous carbon was formed at room-temperature deposition and increased its disorder state with increasing deposition temperature to 500 degC corresponding to higher ratio of disorder peak to graphite peak intensity in Raman spectrum. The crystalline silicon carbide (c-SiC) was formed at 600 degC from the diffracted SiC(111) peak, which is much lower than conventional CVD c-SiC formed at more than 1000 degC. Also, a nanoweb-like morphology of c-SiC was observed on the surface from the SEM image. The atomic composition ratio of Si to carbon was about 54/46 from EDX analysis. Thermal energy is the diving force for the crystalline SiC formation through the interdiffusion between carbon and c-Si. The nanoweb-like morphology may be attributed the high surface energy of SiC with strong Si-C bonding.