SiC surface flattening by large-sized Ar clusters based on the GCIB technique

During the precision machining of superhard materials such as silicon carbide (SiC), the residual surface roughness could significantly affect device performance. In this study, a molecular dynamics (MD) model was constructed to understand the SiC surface flattening mechanism induced by large-sized Ar clusters under gas cluster ion beam (GCIB) bombardment. It has been demonstrated that as the incident cluster energy increases, the SiC surface roughness displays a non-monotonic trend of decreasing and then increasing, while the sputtering depth gradually deepens. The results show that an optimal incident cluster energy exists, and it is approximately 15 keV for Ar 5000 clusters. In this case, the flattening effect is the most significant, and the surface root mean square (RMS) value can be decreased to 6.4 Å. Meanwhile, the sputtering depth can be effectively controlled. The result provides guidance for optimizing the energy parameters in the ultra-precision machining of SiC in GCIB technology.