Get access

Fabrication of Deep Silicon Microstructures by the Combination of Anodization and p++ Etch Stop

Authors

  • Takeo Ohno,

    Non-member, Corresponding author
    1. Micro Nanomachining Research and Education Center, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai 980-8579, Japan
    • MANA Atomic Electronics Group, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
    Search for more papers by this author
  • Shuji Tanaka,

    Member
    1. Department of Nanomechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai 980-8579, Japan
    Search for more papers by this author
  • Masayoshi Esashi

    Member
    1. Micro Nanomachining Research and Education Center, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai 980-8579, Japan
    Search for more papers by this author

Abstract

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. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Ancillary