Effect of substrate temperature on the in-situ formation of crystalline SiC nanostructured film using ultra-high-vacuum ion beam sputtering

In this paper, we have investigated the effect of substrate temperature on the in-situ formation of crystalline SiC (c-SiC) nanostructured film using ultra-high-vacuum ion beam sputtering (UHV IBS). The phase transformation, bonding behavior, morphology, composition and interdiffusion of the SiC nanostructured film were examined by X-ray diffraction, Raman spectra, high resolution scanning electron microscopy (SEM) with the attached energy dispersive X-ray detector and Auger electron spectroscopy (AES) depth profile, respectively. The in-situ formation of c-SiC was through interdiffusion and reaction between the sputtered carbon (C) and the crystalline Si (c-Si) substrate at high temperature. The amorphous-like C microstructure is stable up to 500 °C and transformed into a new phase of c-SiC together with the remained C at 600 °C. Complete C and Si reaction was found at 700 °C from Raman spectra without any C peaks. The main diving force for the c-SiC formation is the thermal energy to activate the large interdiffusion between C and c-Si which was detected from AES depth profile. Also, a nanoweb-like morphology of the c-SiC was observed on the surface of film from the SEM image. Therefore, the c-SiC nanostructured film can be obtained at 700 °C using in-situ UHV IBS process, which is much lower than conventional CVD c-SiC.