基于WO3/Fe3+的可见光催化SiC化学机械抛光工艺研究OA

The work aims to explore a new visible-light-catalyzed chemical and mechanical polishing method for SiC,to achieve efficient and ultra-precise processing of single-crystal SiC under visible light irradiation.The oxidizing properties of polishing solutions in different reaction systems(Fe3+/H2O2,Vis/TiO2/H2O2,Vis/WO3/H2O2,Vis/TiO2/Fe3+/H2O2,Vis/WO3/Fe3+/H2O2)were systematically analyzed through methyl orange decolorization experiments,electrochemical tests,immersion corrosion experiments,and polishing experiments,combined with detection results from instruments such as an electrochemical workstation,scanning electron microscope(SEM),X-ray energy dispersive spectrometer(EDS),and X-ray photoelectron spectroscope(XPS).The removal rate of SiC polishing materials was calculated with the weight loss method,and the surface roughness and morphology of polished SiC were obtained via a 3D surface profiler.The effects of polishing solutions from different reaction systems on the removal rate of SiC polishing materials and surface quality were investigated,revealing the mechanism of visible-light-catalyzed chemical and mechanical polishing of SiC based on WO3/Fe3+.Under the optimal reaction system conditions(Vis/WO3/Fe3+/H2O2),diamond/SiO2 mixed abrasives were further introduced.Through comparative experiments of polishing SiC with or without a light source(wavelength 425 nm),the feasibility of polishing visible-light-catalyzed SiC with diamond/SiO2 mixed abrasives was preliminarily verified.Experimental results showed that among the five different reaction system solutions,the Vis/WO3/Fe3+/H2O2 reaction system solution had the shortest decolorization time for methyl orange,the highest electrochemical corrosion potential,and the highest oxygen content on the SiC surface after immersion corrosion(9.48at.%),indicating the strongest oxidative ability of the solution.Under this reaction system,using SiO2 abrasive to polish SiC resulted in a material removal rate of 279.83 nm/h and a surface roughness Sa of 55.73 nm,achieving the best polishing effect compared to the other reaction systems.In the comparative experiment of polishing SiC with diamond/SiO2 mixed abrasives under conditions with and without visible light,the polishing effect of diamond/SiO2 mixed abrasives under visible light was better,with a further increase in material removal rate.After 0.5 hours of polishing,the surface roughness Sa of SiC significantly decreased from 120 nm to 0.861 nm.Analysis of the experimental results showed that under visible light irradiation,Fe3+promoted the visible light photocatalytic reaction.Compared with the TiO2 photocatalyst,Fe3+had a more significant promoting effect on the visible light photocatalytic reaction of WO3.The Fe3+reacted with photogenerated electrons in the conduction band of WO3,reducing Fe3+to Fe2+,which greatly decreased the recombination of WO3 photogenerated electron-hole pairs and enhanced the photocatalytic efficiency of WO3.At the same time,the generated Fe2+underwent a Fenton reaction with H2O2 in the solution,creating a synergistic effect between visible light photocatalysis and the Fenton reaction.This increased the concentration of highly oxidative hydroxyl radicals in the polishing solution,significantly improving the oxidation ability and polishing effect of the solution on SiC.Through comparative experiments of SiC polishing under conditions with and without visible light,the feasibility of polishing SiC with diamond/SiO2 mixed abrasives in a Vis/WO3/Fe3+/H2O2 visible light catalytic reaction system was preliminarily verified.By combining the chemical action of the polishing slurry under visible light catalysis with the mechanical action of the diamond/SiO2 mixed abrasives,SiC wafers with high material removal rates and relatively good surface quality were obtained.