Polishing Removal Rate And Corrosion Electrochemistry Of Mono-crystalline Silicon Carbide Materials

With the rapid development of science and technology and the rapid development of semiconductor technology,the third generation of semiconductor materials represented by silicon carbide has attracted worldwide attention.Single crystal silicon carbide is used as an epitaxial growth substrate material and a high power semiconductor device,and superior quality is required for the planarization quality.Chemical mechanical polishing(CMP)can achieve a high degree of flatness on the SiC surface,thereby improving the performance of SiC-based devices.After investigating the potentiodynamic polarization curves of silicon carbide in in NaClO system,K2S2O8 system and H2O2 system,the following rules were summarized: in NaClO system,when different NaClO concentrations were used,the corrosion potential first decreased and then increased,and the concentration of NaClO is 5vol.%,the corrosion potential reached a minimum of-89 m V,and the corrosion effect achieved the best optimizations.In the K2S2O8 system,with the rising of K2S2O8 concentration,the corrosion potential of SiC decreased first and then increased.When the concentration was 5 m M,the corrosion potential reached-129 m V,and the corrosion effect was the best.Under ultraviolet light,the concentration of K2S2O8 is 5 m M,and the corrosion potential with Zn O as the catalyst is-189 m V.In the hydrogen peroxide system,as the concentration of H2O2 increased,the corrosion potential decreased first and then increased.When the concentration of H2O2 was 5 vol.%,the corrosion potential was at least-176 m V.When the concentration of H2O2 was 5 vol.%,the corrosion potential gradually decreased with the rising of p H,and the corrosion potential was-51 m V at p H=12.In the ultraviolet irradiation system,the concentration of H2O2 was 5 vol.%,and the corrosion potential with Zn O as the catalyst was-34 m V.Under the condition of ultraviolet light,when the concentration of H2O2 was 5vol.%,the corrosion potential decreased first and then increased with the rising of the concentration of ferric nitrate.The corrosion potential is the lowest at 7 m M and it was-165 m V.Under ultraviolet light,the concentration of H2O2 was 5 vol.%.When the molar ratio of ferric nitrate to oxalic acid was 1:1.5,the corrosion potential was the lowest,and it was-121 m V.The polishing results are as follows: When NaClO was used as the oxidant system,the removal rate of SiC silicon surface is 166.7 nm/h when the concentration is 5vol.% and the p H is 9.5.The removal rate after polishing with a polishing solution containing 5 m M K2S2O8 and 0.05 wt% Zr O2 under ultraviolet light was the highest of the three catalysts(Ti O2,Zn O,Zr O2)of 307.4 nm/h.When the concentration of H2O2 was 5vol.%,the removal rate of SiC silicon surface can reach 285.7 nm/h when the p H was 12.Under ultraviolet light,the removal rate of SiC silicon surface obtained by using 5vol.% H2O2 and 0.05 wt% Zr O2 was the highest among the three catalysts(Ti O2,Zn O,Zr O2)of 430.4 nm/h.The SiC surface was analyzed by XPS,and it was found that the product contained Si-C bonds,Si-O bonds,and Si-C-O bonds.Finally,the surface roughness of the polished SiC surface was tested by atomic force microscopy.The surface roughness Rq of the SiC Si surface after polishing with 5vol.% NaClO as the oxidant system was 4.36 nm.The surface roughness Rq after polishing with 5 m M K2S2O8,0.05 wt% Zr O2 polishing solution was 2.88 nm.The surface roughness Rq after polishing with 5vol.% H2O2 and 0.05 wt% Zr O2 polishing solution was 2.56 nm.