The structure-mechanical property relationship of amorphous silicon monoxide thin films

Abstract

Amorphous silicon monoxide (SiO x ) thin films were produced by Joule heating and electron bombardment evaporative methods in high vacuum. Real-time force vs. elongation curves were recorded for SiO x films 200–300 nm thick on an instrument known as the nanotensilometer. The elastic modulus, fracture stress and plastic deformation were determined from hard mode tensile testing. The elastic modulus varied from 53 to 75 GPa independent of film preparation method. No plastic deformation was detected for successive tensile pulls on a given specimen. Estimates of plastic deformation never exceeded 0.015% strain at the point of fracture. Failure occurred by brittle fracture and fracture stress ranged from 70 to 380 MPa. The film composition determined by Rutherford scattering gave an x value in SiO x within the range 0.9–1.0 for all films independent of evaporation method. The structure of the SiO x was determined to be of an amorphous character by electron diffraction and structure imaging using transmission electron microscopy.