▎ 摘　　要

In this paper, a functional ternary slurry consisting of polyurethane (PU) microspheres, graphene oxide (GO) nano platelets and silicon oxide (SiO2) abrasives was used to carry out the polishing process on Si face of 4H-SiC wafers. The processing parameters of the slurry include graphene weight fraction in slurry GO1-GO7 (0.1-0.7 wt.%), pH value (3-5), and sonication time T5-T15 (5-15 min). Polishing process is conducted with two kinds of polishing pads A and B, PU and PC (polycarbonate). Results show that material removal rate (MRR) increases with increasing GO weight fraction up to GO5; besides, MRR also increases with increasing sonication time up to T10, and with increasing pH value. Using PU pad, the GO5-T10-pH5-A slurry leads to highest MRR 102.220 nm/h of the polished SiC wafer. On the other hand, surface roughness improvement rate (SRIR) increases with increasing GO weight fraction up to GO5, and increases with increasing sonication time up to T15. But SRIR is not affected by pH value. Regarding effect of pad type, on average the PU pad results in higher MRR and better SRIR compared with the PC pad. Using PC pad, GO5-T10-pH5-B leads to lower MRR of 87.627 nm/h. The addition of GO as the ternary slurry demonstrates its better effect on polishing SiC wafers by comparing with the counterpart binary slurry without GO. For example, MRR by the counterpart slurry SiO(2)12-pH5-A is 58.411 nm/h, which is lower than 102.220 nm/h by the ternary slurry GO5-T10-pH5-A. Both XPS and Raman spectra demonstrate that the wafer polished by the functional ternary slurry can effectively produce the softer SiO2 reactant layer on SiC wafer, and result in better polishing performance.