Atomic-Scale Surface Formation of 4H–SiC during Chemical Mechanical Polishing through Catalyst-Induced Dual-Pathway Oxidation

Achieving appreciable material removal while preserving atomic-scale surface integrity remains challenging in CMP of 4H–SiC, largely because the oxidation pathways governing catalyst-assisted removal are still insufficiently understood. Here, a NaVO3–H2O2–SiO2 slurry was employed as a model catalytic system to clarify how H2O2 activation controls interfacial oxidation and material removal during CMP. Compared with a conventional H2O2–SiO2 slurry, the NaVO3-containing system increased the MRR from 27 to 366 nm h–1 while producing an atomically smooth surface with Sa below 0.1 nm. Combined experiments and first-principles calculations reveal that this enhancement originates from a catalyst-induced dual-pathway oxidation mechanism. In the first pathway, NaVO3 activates H2O2 to form pervanadate species, represented by [VO(O2)(OH)2]−, which directly oxidize surface Si–C bonds and initiate the formation of a SiO2-rich tribolayer. In the second pathway, reduced V(IV) intermediates further react with H2O2 through a Fenton-like route to generate hydroxyl radicals, which sustain tribolayer renewal and deepen surface oxidation. Electrochemical measurements, UV–vis spectroscopy, XPS, cross-sectional TEM, and density functional theory consistently support this mechanism. These results establish a mechanistic framework linking catalytic H2O2 activation, interfacial oxidation, tribolayer evolution, and atomic-scale surface formation in 4H–SiC CMP.