Insight into the atomic-scale material removal of 4H-SiC electrochemical mechanical polishing (ECMP) using graphene oxide

Silicon carbide (SiC), owing to its excellent properties and extensive application, has been regarded as a promising semiconductor material. Nevertheless, due to the high hardness and chemical inertness of 4H-SiC, the improvement in the polishing efficiency remains a significant challenge for the industry. An ultra-precision polishing approach of electrochemical mechanical polishing (ECMP) by using the slurry, which contained the diamond abrasives and graphene oxide (GO), was presented. The single crystal 4H-SiC wafers were processed with ECMP using the slurry of 1 wt% diamond+ 0/0.25/0.5/0.75/1 wt% GO+ 1 wt% NaCl+ deionized water. Furthermore, the SiC-ECMP performance of material removal rate (MRR) and surface roughness (R_a) was investigated. In addition, the atomic force microscopy (AFM) morphologies of the pre-ECMP and post-ECMP 4H-SiC wafers were observed, respectively. The characteristics of ECMP slurry were conducted as well. The optimized SiC-ECMP process achieved an MRR of 2.32 μm/h and a R_a of 0.287 nm, demonstrating the feasibility of implementing an eco-friendly polishing process through precise control of slurry composition (diamond abrasives+ GO). This combination enables high-efficiency material removal and atomic-level surface quality while maintaining the environmental sustainability. This study offers a useful exploration in revealing the SiC-ECMP material removal mechanisms with the help of molecular dynamics (MD) simulations.