Strength of ultrananocrystalline diamond thin films - Identification of Weinbull parameters

B. Peng, Horacio Dante Espinosa*, N. Moldovan, X. Xiao, O. Auciello, J. A. Carlisle, D. M. Gruen, R. S. Divan, D. C. Mancini, J. E. Gerbi, J. Birrell

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

Abstract

The fracture strength of ultrananocrystalline diamond (UNCD) thin films, grown by microwave-plasma-enhanced chemical-vapor deposition (PECVD), was measured using the membrane deflection experiment (MDE) developed by Espinosa and coworkers. The data show that UNCD fracture strength appears to follow a Weibull distribution. Furthermore, we show that the Weibull parameters are highly dependent on the seeding process used in the growth of the films. When seeding was performed with micron-size diamond particles, using mechanical polishing of the substrate, the stress, resulting in a probability of failure of 67%, was found to be 1.74 GPa, and the Weibull modulus was 5.74. By contrast, when seeding was performed with nano-size diamond particles, using ultrasonic agitation, the stress, resulting in a probability of failure of 67%, increased to 4.13 GPa and the Weibull modulus was 10.76. The investigation highlights the role of microfabrication defects on material properties and reliability, as a function of seeding technique, when identical PECVD chemistry is employed. The parameters identified in this study are expected to aid the designer of MEMS/NEMS devices employing UNCD films.

Original languageEnglish (US)
Pages (from-to)49-54
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume778
StatePublished - Dec 1 2003
EventMechanical Properties Derived from Nanostructuring Materials - San Francisco, CA, United States
Duration: Apr 22 2003Apr 25 2003

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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