Development of lapping and polishing technologies of 4H-SiC wafers for power device applications

Hirokatsu Yashiro, Tatsuo Fujimoto, Noboru Ohtani, Taizo Hoshino, Masakazu Katsuno, Takashi Aigo, Hiroshi Tsuge, Masashi Nakabayashi, Hosei Hirano, Kohei Tatsumi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

9 Citations (Scopus)

Abstract

The development of lapping and polishing technologies for SiC single crystal wafers has realized the fabrication of an extremely flat SiC wafer with excellent surface quality. To improve the SiC wafer flatness, we developed a four-step lapping process consisting of four stages of both-side lapping with different grit-size abrasives. We have applied this process to lapping of 2-inch-diameter SiC wafers and obtained an excellent flatness with TTV (total thickness variation) of less than 3 μm, LTV (local thickness variation) of less than 1 μm, and SORI smaller than 10 μm. We also developed a novel MCP (mechano-chemical polishing) process for SiC wafers to obtain a damage-free smooth surface. During MCP, oxidizing agents added to colloidal silica slurry, such as NaOCl and H2O2, effectively oxidize the SiC wafer surface, and then the resulting oxides are removed by colloidal silica. AFM (atomic force microscope) observation of polished wafer surface revealed that this process allows us to have excellent surface smoothness as low as Ra=0.168 nm and RMS=0.2 nm.

Original languageEnglish
Title of host publicationSilicon Carbide and Related Materials 2007
EditorsAkira Suzuki, Hajime Okumura, Kenji Fukuda, Shin-ichi Nishizawa, Tsunenobu Kimoto, Takashi Fuyuki
PublisherTrans Tech Publications Ltd
Pages819-822
Number of pages4
ISBN (Print)9780878493579
DOIs
Publication statusPublished - 2009 Jan 1
Externally publishedYes
Event12th International Conference on Silicon Carbide and Related Materials, ICSCRM 2007 - Otsu, Japan
Duration: 2007 Oct 142007 Oct 19

Publication series

NameMaterials Science Forum
Volume600-603
ISSN (Print)0255-5476
ISSN (Electronic)1662-9752

Conference

Conference12th International Conference on Silicon Carbide and Related Materials, ICSCRM 2007
CountryJapan
CityOtsu
Period07/10/1407/10/19

Keywords

  • 4H-SiC
  • Atomic force microscopy
  • Auger electron spectroscopy
  • Lapping
  • LTV
  • Mechano-chemical polishing
  • SORI
  • TTV

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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  • Cite this

    Yashiro, H., Fujimoto, T., Ohtani, N., Hoshino, T., Katsuno, M., Aigo, T., Tsuge, H., Nakabayashi, M., Hirano, H., & Tatsumi, K. (2009). Development of lapping and polishing technologies of 4H-SiC wafers for power device applications. In A. Suzuki, H. Okumura, K. Fukuda, S. Nishizawa, T. Kimoto, & T. Fuyuki (Eds.), Silicon Carbide and Related Materials 2007 (pp. 819-822). (Materials Science Forum; Vol. 600-603). Trans Tech Publications Ltd. https://doi.org/10.4028/3-908453-11-9.819