Structure variation and annealing effect on mechanical properties of single carbon films

The aim of this study is to investigate the effect of thickness variation, rapid thermal annealing and silicon layer addition on mechanical property of single carbon film by using nanoindentation. From the results, Raman spectra showed that I_D/I_G ratio decreased with increasing carbon film thickness on single-layer structure at room temperature (RT). The higher the I_D/I_G, the more the sp² bonds are. The evolution of both hardness and Young's modulus of films had the inverse trend as the formation of sp² bond. Therefore, it is noted that less sp² bond formation was beneficial to enhance the hardness and Young's modulus of single carbon layer structure. Compared with single-layer structure, hardness and Young's modulus of C/Si two-layer decreased through Si addition. Under thermal treatment process, it can be found that hardness and Young's modulus decreased at 750°C due to graphitization then the SiC was formed at higher annealing temperature on the surface of two-layer structure lead to hardness enhancement.