The nanomechanics of tetrahedral amorphous diamond-like carbon (ta-C) MEMS

I. Chasiotis, T. A. Friedmann, S. W. Cho, J. P. Sullivan

Research output: Contribution to conferencePaperpeer-review


The mechanics of hydrogen-free tetrahedral amorphous diamond-like carbon (ta-C) MEMS structures have been investigated in connection with their elastic and failure properties. For this purpose, micro-tension specimens of thicknesses between 1.2 urn and 1.8 urn and gage widths of 10 μm or 50 μm have been fabricated by the Sandia National Laboratories (SNL). The mechanical characterization has been conducted via in situ AFM measurements and Digital Image Correlation (DIG) data strain analysis and the deformation fields of uniform tension specimens and internally notched specimens with acute notches (K=27) have been experimentally obtained. The elastic modulus and Poisson's ratio were measured for the first time directly from the specimens averaging 750 GPa and v=0.16 respectively, while the tensile strength was found to be very consistent averaging 7.0 GPa. Stressed material domains with smaller dimensions in the vicinity of micronotches exhibited even higher failure strength reaching an average of 11.5 GPa with about 10% scatter. AFM images of specimens under high tensile stresses have also indicated the possibility of an sp3 to sp2 phase transformation on the film surface at very high tensile stresses (>6 GPa).

Original languageEnglish (US)
Number of pages5
StatePublished - 2003
Externally publishedYes
Event2003 ASME International Mechanical Engineering Congress - Washington, DC, United States
Duration: Nov 15 2003Nov 21 2003


Other2003 ASME International Mechanical Engineering Congress
Country/TerritoryUnited States
CityWashington, DC

ASJC Scopus subject areas

  • Mechanical Engineering
  • Electrical and Electronic Engineering


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