Preliminary Study on Highly Efficient Polishing of 4H-SiC by Utilization of Anodic Oxidation

Abstract:

Preliminary study on anodic-oxidation-assisted polishing (AOAP) of 4H-SiC (0001) using ceria polishing film was demonstrated. In the case of using deionized (DI) water as an electrolyte, rms roughness of 0.16 nm was obtained, which is almost the same as roughness of the surface finished by conventional chemical mechanical polishing (CMP). However, the polishing rate was very low and was 23 nm/h. In contrast, the polishing rate of 0.84 μm/h, which is equal to that of conventional CMP of single-crystal SiC or greater, was obtained when we used 1 wt% of phosphoric acid (H₃PO₄) as the electrolyte, although the surface roughness increased to rms roughness of 1 nm order. These experimental results indicate that the polishing rate greatly depends on the oxidation rate of anodic oxidation and the balance between the oxidation rate and the removal rate of oxide by abrasive greatly affects the roughness of the processed surface.

• Periodical: Advanced Materials Research (Volume 1017)
• Pages: 509-514
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1017.509
• Online since: September 2014
• Authors: Kazuya Yamamura*, Kenji Hosoya, Yusuke Imanishi, Hui Deng, Katsuyoshi Endo
• Keywords: 4H-SiC, Anodic Oxidation, Anodic-Oxidation-Assisted Polishing, Damage-Free, Polishing

References

[1] L. Zhou, V. Audurier, P. Pirouz, Chemomechanical polishing of silicon carbide, J. Electrochem. Soc. 144 (1997) L161-163.

DOI: 10.1149/1.1837711

[2] H. S, Lee, H. D, Jeong, Chemical and mechanical balance in polishing of electronic materials for defect-free surfaces, Annals of the CIRP 58(1) (2009) 485-490.

DOI: 10.1016/j.cirp.2009.03.115

[3] H. S. Lee, D. I. Kim, J. H. An, H. J. Lee, K. H. Kim, H. Jeong, Hybrid polishing mechanism of single crystal SiC using mixed abrasive slurry (MAS), Annals of the CIRP 59(1) (2010) 333-336.

DOI: 10.1016/j.cirp.2010.03.114

[4] K. Arima, H. Hara, J. Murata, T. Ishida, R. Okamoto, K. Yagi, Y. Sano, H. Mimura, K. Yamauchi, Atomic-scale flattening of SiC surfaces by electroless chemical etching in HF solution with Pt catalyst, Appl. Phys. Lett. 90 (2007) 202106-1-3.

DOI: 10.1063/1.2739084

[5] J. Watanabe, S. H. Hong, K. Yamaguchi, M. Touge, N. Kuroda, Effect of TiO2 and CeO2 particles on SiC semiconductor surfaces polished under ultraviolet-ray irradiation, Proc. Advances in Abrasive Technology (ASAAT 2007), Michigan, USA (2007) 91-96.

[6] K. Yamamura, T. Takiguchi, M. Ueda, H. Deng, A.N. Hattori, N. Zettsu, Plasma assisted polishing of single crystal SiC for obtaining atomically flat strain-free surface, Annals of the CIRP 60 (2011) 571-574.

DOI: 10.1016/j.cirp.2011.03.072

[7] H. Deng, K. Yamamura, Atomic-scale flattening mechanism of 4H-SiC (0001) in plasma assisted polishing, Annals of the CIRP 62 (2013) 575-578.

DOI: 10.1016/j.cirp.2013.03.028

[8] H. Deng, K. Endo, K. Yamamura, Comparison of thermal oxidation and plasma oxidation of 4H-SiC (0001) for surface flattening, Appl. Phys. Lett. 104 (2014) 101608.

DOI: 10.1063/1.4868487

[9] C. Li, I. B. Bhat, R. Wang, J. Seiler, Electro-chemical mechanical polishing of silicon carbide, J. Electron. Mater. 33 (2004) 481-486.

DOI: 10.1007/s11664-004-0207-6

[10] T. Kurita, K. Miyake, K. Kawata, K. Ashida, T. Kato, Development of new combined polishing process for single crystal silicon carbide, Journal of the Japan Society for Abrasive Technology 58 (2014) 30-35 (in Japanese).

DOI: 10.1115/1.4036828

[11] K. Yamamura, Japanese patent application No. 2013-060147 (2013).