Tribology Letters

, 44:13 | Cite as

Morphological, Electrical, and Chemical Changes in Cyclically Contacting Polycrystalline Silicon Surfaces Coated with Perfluoroalkylsilane Self-Assembled Monolayer

  • Ian Laboriante
  • Maxwell Fisch
  • Amir Payamipour
  • Fang Liu
  • Carlo Carraro
  • Roya Maboudian
Original Paper

Abstract

The evolution of morphology, electrical properties, and chemical composition has been studied in cyclically contacting polycrystalline silicon (polysilicon) surfaces coated with perfluoroalkylsilane self-assembled monolayer (SAM). The microinstrument used is a MEMS cantilever that is repeatedly actuated out-of-plane to impact a landing pad and is then moved in-plane to enable nondestructive in situ inspection of the impacted area. Analyses show that a device with a monolayer coating exhibits signs of surface degradation after a much higher number of cycles than its uncoated counterpart. A sharp increase in contact resistance between the cantilever and landing pad is observed at ~10 billion cycles for a coated device, versus ~25 million cycles for an uncoated device. Likewise, the onset of grain fracture in the landing pad occurs at ~25 billion cycles for the SAM-coated device, versus ~3 billion cycles for its uncoated counterpart. The effectiveness of the monolayer coating diminishes after more than 100 billion contact cycles as the SAM layer is removed, and the polysilicon substrate becomes susceptible to adhesive wear.

Keywords

MEMS reliability Polycrystalline silicon Contact resistance Self-assembled monolayer Multi-asperity contacts Adhesive wear 

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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Ian Laboriante
    • 1
    • 2
  • Maxwell Fisch
    • 1
  • Amir Payamipour
    • 1
  • Fang Liu
    • 1
    • 3
  • Carlo Carraro
    • 1
  • Roya Maboudian
    • 1
  1. 1.Department of Chemical and Biomolecular EngineeringUniversity of CaliforniaBerkeleyUSA
  2. 2.Micron TechnologyBoiseUSA
  3. 3.Analog Devices IncWilmingtonUSA

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