Influences of Polishing Slurry Components on Material Removal and Surface Morphology of 4H-SiC C-Face Based on Fenton Reaction CMP

This study systematically investigates the effects of polishing slurry components on the material removal rate (MRR) and surface morphology of the C-face of 4H-SiC substrates during chemical mechanical polishing (CMP) based on the Fenton reaction. By regulating the particle size and concentration of colloidal silica abrasives, H2O2 concentration, and Fe3O4 catalyst content, the mechanisms of each component on MRR and surface roughness (Sa) were systematically analyzed. The results indicate that in an alkaline polishing slurry at pH = 9, Fe3O4 effectively catalyzes the decomposition of H2O2 to generate hydroxyl radicals (·OH), thereby significantly enhancing the material removal efficiency. When using colloidal silica with a particle size of 110 nm at a concentration of 8 wt%, H2O2 at 5 wt%, and Fe3O4 at 0.03 wt%, a maximum MRR of 701 nm/h was achieved along with a good surface quality of Sa = 0.79 nm. The study also found that the abrasive particle size and concentration, as well as the ratio of oxidant to catalyst, significantly influence the chemo-mechanical synergy. Excessively high H2O2 or Fe3O4 concentrations can trigger ·OH quenching reactions, thereby reducing polishing efficiency. This research provides a theoretical basis and process optimization direction for the application of heterogeneous Fenton reactions in SiC CMP under alkaline conditions.