Alkoxyl monolayers as anti-stiction coatings in Si-based MEMS devices

Yongseok Jun, Xiaoyang Zhu

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Reducing surface energy is key to the success of many microelectromechanical systems (MEMS). In this report we present a strategy for the efficient assembly of alkoxyl monolayers onto a silicon surface to control surface energy. This is achieved by an all-liquid process in which the hydrogen terminated silicon surface resulting from aqueous HF etching is coated with a close-packed alkoxyl monolayer. The adhesion to silicon surface is reduced by a factor of 40 by the monolayer coating and friction coefficient of the coated surface is only 10 -2. These coatings are successfully implemented in a model MEMS structure: cantilever beam array (CBA). Release-stiction is eliminated for polycrystalline silicon beams with a thickness of only 2 μm but with lengths up to 2 mm. Electrostatic actuation of coated beams in a controlled environment shows that the monolayer coating prevents in-use stiction at relative humidity as high as 90%.

Original languageEnglish
Pages (from-to)593-601
Number of pages9
JournalJournal of Adhesion Science and Technology
Volume17
Issue number4
DOIs
Publication statusPublished - 2003

Keywords

  • MEMS
  • Monolayer coating
  • friction
  • self-assembled monolayer.
  • silicon
  • stiction
  • surface energy

ASJC Scopus subject areas

  • Chemistry(all)
  • Mechanics of Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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