skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A new bulge test technique for the determination of Young's modulus and Poisson's ratio of thin films

Journal Article · · Journal of Materials Research; (United States)
;  [1]
  1. Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

A new analysis of the deflection of square and rectangular membranes of varying aspect ratio under the influence of a uniform pressure is presented. The influence of residual stresses on the deflection of the membranes is examined. Expressions have been developed that allow one to measure residual stresses and Young's moduli. By testing both square and rectangular membranes of the same film, it is possible to determine Poisson's ratio of the film. Using standard micromachining techniques, free-standing films of LPCVD silicon nitride were fabricated and tested as a model system. The deflection of the silicon nitride films as a function of film aspect ratio is very well predicted by the new analysis. Young's modulus of the silicon nitride films is 222[plus minus]3 GPa and Poisson's ratio is 0.28[plus minus]0.05. The residual stress varies between 120 and 150 MPa. Young's modulus and hardness of the films were also measured by means of nanoindentation, yielding values of 216[plus minus]10 GPa and 21.0[plus minus]0.9 GPa, respectively.

DOE Contract Number:
FG03-89ER45387
OSTI ID:
6838055
Journal Information:
Journal of Materials Research; (United States), Vol. 7:12; ISSN 0884-2914
Country of Publication:
United States
Language:
English