IJAT Vol.15 No.1 pp. 74-79
doi: 10.20965/ijat.2021.p0074


Photoelectrochemical Oxidation Assisted Catalyst-Referred Etching for SiC (0001) Surface

Daisetsu Toh*,†, Pho Van Bui*, Kazuto Yamauchi*,**, and Yasuhisa Sano*

*Department of Precision Engineering, Graduate School of Engineering, Osaka University
2-1 Yamada-Oka, Suita, Osaka 565-00817, Japan

Corresponding author

**Research Center for Ultra-Precision Science and Technology, Graduate School of Engineering, Osaka University, Osaka, Japan

May 21, 2020
September 16, 2020
January 5, 2021
catalyst-referred etching, silicon carbide (SiC), photoelectrochemical oxidation (PEC), ultraviolet light

In a previous study, we developed an abrasive-free polishing method named catalyst-referred etching (CARE) and used it for the planarization of silicon carbide (SiC) (0001). In this method, Si atoms at step edges are preferentially removed through a catalytically assisted hydrolysis reaction to obtain an atomically smooth and crystallographically well-ordered surface. However, the removal rate is low (< nm/h) and needs to be improved. In this study, we proposed an ultraviolet (UV) light assisted CARE method. In this method, UV light is irradiated onto a SiC surface to generate holes and oxidize the surface. The oxidized area, consisting of SiO2, can be quickly removed to form a nano-pit owing to the higher removal rate of SiO2 compared to that of SiC. The periphery of the nano-pits works as a reaction site, leading to a higher removal rate. To enhance the oxidation rate and form nano-pits, we applied electrochemical bias to the SiC substrate. However, the removal rate did not improve significantly when the bias voltage was higher than 3.0 V. This is because the electrochemical potential of Pt increased with the anodic potential of SiC, which oxidized the Pt surface and degraded the catalyst capability. To avoid this issue, we modified the catalytic pad, where an in-situ refreshment of the Pt surface is possible. As a result, the removal rate increased up to 200 nm/h at a bias of 7.0 V, which is 100 times higher than that of the CARE without UV irradiation. The proposed method is expected to contribute to the enhancement in the productivity and quality of next-generation SiC substrates.

Cite this article as:
Daisetsu Toh, Pho Van Bui, Kazuto Yamauchi, and Yasuhisa Sano, “Photoelectrochemical Oxidation Assisted Catalyst-Referred Etching for SiC (0001) Surface,” Int. J. Automation Technol., Vol.15, No.1, pp. 74-79, 2021.
Data files:
  1. [1] H. Lee, V. Smet, and R. Tummala, “A review of SiC power Module Packaging Technologies: Challenges, Advances, and Emerging Issues,” IEEE J. of Emerging and Selected Topics in Power Electronics, Vol.8, pp. 239-255, 2020.
  2. [2] R. Komanduri, D. A. Lucca, and Y. Tani, “Technological advances in fine abrasive processes,” CIRP Ann., Vol.46, pp. 545-596, 1997.
  3. [3] P. B. Zantye, A. Kumar, and A. K. Sikder, “Chemical mechanical planarization for microelectronics applications,” Mater. Sci. Eng. R. Rep., Vol.45, pp. 89-220, 2004.
  4. [4] M. Uneda, K. Takano, K. Koyama, H. Aida, and K. Ishikawa, “Investigation into Chemical Mechanical Polishing Mechanism of Hard-to-Process Materials Using a Commercially Available Single-Sided Polisher,” Int. J. Automation Technol., Vol.9, No.5, pp. 573-579, 2015.
  5. [5] J. Luo and D. A. Dornfeld, “Material removal mechanism in chemical mechanical polishing: Theory and modeling,” IEEE Trans. Semicond. Manuf., Vol.14, pp. 112-133, 2001.
  6. [6] M. Krishnan, J. W. Nalaskowski, and L. M. Cook, “Chemical mechanical planarization: Slurry chemistry, materials, and mechanisms,” Chem. Rev., Vol.110, pp. 178-204, 2010.
  7. [7] V. T. Nguyen and T. H. Fang, “Molecular dynamics simulation of abrasive characteristics and interfaces in chemical mechanical polishing,” Appl. Surf. Sci., Vol.509, 144676, 2020.
  8. [8] A. Chandra, P. Karra, A. F. Bastawros, R. Biswas, P. J. Sherman, S. Armini, and D. Lucca, “Prediction of scratch generation in chemical mechanical planarization,” CIRP Ann., Vol.57, pp. 559-562, 2008.
  9. [9] N. Saka, T. Eusner, and J. H. Chun, “Nano-scale scratching in chemical-mechanical polishing,” CIRP Ann., Vol.57, pp. 341-344, 2008.
  10. [10] H. Hara, Y. Sano, H. Mimura, K. Arima, A. Kubota, K. Yagi, J. Murata, and K. Yamauchi, “Novel abrasive-free planarization of 4H-SiC (0001) using catalyst,” J. Electron. Mater., Vol.35, pp. L11-L14, 2006.
  11. [11] Y. Sano, K. Arima, and K. Yamauchi, “Planarization of SIC and GaN wafer using polishing technique utilizing catalyst surface reaction,” ESC J. Solid State Sci. Technol., Vol.2, pp. N3028-N3035, 2013.
  12. [12] P. V. Bui, Y. Sano, Y. Morikawa, and K. Yamauchi, “Characteristics and Mechanism of Catalyst-Referred Etching Method: Application to 4H-SiC,” Int. J. Automation Technol., Vol.12, No.2, pp. 154-159, 2018.
  13. [13] A. Isohashi, P. V. Bui, D. Toh, S. Matsuyama, Y. Sano, K. Inagaki, Y. Morikawa, and K. Yamauchi, “Chemical etching of silicon carbide in pure water by using platinum catalyst,” Appl. Phys. Lett., Vol.110, 201601, 2017.
  14. [14] J. Murata, S. Sadakuni, T. Okamaoto, A. N. Hattori, K. Yagi, Y. Sano, K. Arima, and K. Yamauchi, “Structural and chemical characteristics of atomically smooth GaN surfaces prepared by abrasive-free polishing with Pt catalyst,” J. Cryst. Growth, Vol.349, pp. 83-88, 2012.
  15. [15] D. Toh, P. V. Bui, A. Isohashi, N. Kidani, S. Matsuyama, Y. Sano, Y. Morikawa, and K. Yamauchi, “Catalyzed chemical polishing of SiO2 glasses in pure water,” Rev. Sci. Instrum., Vol.90, 045115, 2019.
  16. [16] T. Okamoto, Y. Sano, K. Tachibana, P. V. Bui, K. Arima, K. Inagaki, K. Yagi, J. Murata, S. Sadakuni, H. Asano, A. Isohashi, and K. Yamauchi, “Improvement of removal rate in abrasive-free planarization of 4H-SiC substrate using catalyst platinum and hydrofluoric acid,” Jpn. J. Appl. Phys., Vol.51, 046501, 2012.
  17. [17] H. Kida, D. Toh, P. V. Bui, A. Isohashi, R. Ohnishi, S. Matsuyama, K. Yamauchi, and Y. Sano, “High-efficiency planarization of SiC wafers by water-CARE (Catalyst-referred etching employing photoelectrochemical oxidation,” Mater. Sci. Forum, Vol.963, pp. 525-529, 2018.
  18. [18] G. Nowask, X. H. Xia, J. J. Kelly, J. L. Weyher, and S. Porowski, “Electrochemical etching of highly conductive GaN single crystals,” J. Cryst. Growth, Vol.222, pp. 735-740, 2001.
  19. [19] M. Pourbaix, “Atlas of Electrochemical Equilibria in Aqueous Solutions,” National Association of Corrosion Engineers (NACE), 1966.
  20. [20] K. Kojima, K. Masumoto, S. Ito, A. Nagata, and H. Okumura, “4H-SiC homoepitaxial growth on substrate with vicinal off-angle lower than 1,” ECS J. Solid State Sci. Technol., Vol.2, pp. N3012-N3017, 2013.
  21. [21] K. Masumoto, H. Asamizu, K. Tamura, C. Kudou, J. Nishio, K. Kojima, T. Ohno, and H. Okumura, “Suppression of 3C-inclusion formation during growth of 4H-SiC Si-Face homoepitaxial layers with a 1 off-angle,” Materials, Vol.7, pp. 7010-7021, 2014.

*This site is desgined based on HTML5 and CSS3 for modern browsers, e.g. Chrome, Firefox, Safari, Edge, Opera.

Last updated on Mar. 05, 2021