Fabrication of deep silicon microstructures by the combination of anodization and p++ etch stop

Takeo Ohno, Shuji Tanaka, Masayoshi Esashi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


In order to fabricate deep silicon (Si) microstructures with possibly vertical sidewalls by wet etching, macroporous Si was formed in a Si substrate by anodization using a hydrofluoric-acid (HF)-based solution with backside illumination. The shape of microstructures such as fixed-fixed beams and cantilevers were defined by boron (B) diffusion, and the B-diffused microstructures were left by a p++ etch stop after etching the macroporous Si in tetramethyl ammonium hydroxide. The B-diffused microstructures were fabricated, but the sidewalls were not as vertical as expected, but were inclined at 40°-60° to the substrate surface, due to undercutting during anodization. The reason for the undercutting is discussed.

Original languageEnglish
Pages (from-to)493-497
Number of pages5
JournalIEEJ Transactions on Electrical and Electronic Engineering
Issue number4
Publication statusPublished - 2010 Jul


  • Anodization
  • Deep wet etching
  • Etch stop
  • Si microstructure

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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