Elastic Properties of Dense Organosilicate Glasses Dependent on the C/Si Ratio
Organosilicate glasses (OSG) are of great technological interest as low-k dielectrics. We use ab initio simulations to analyze the influence of the C/Si ratio in OSG on the density and elastic properties of pore-free material to gain a detailed understanding of the origins of these properties in this class of materials. We find that the addition of carbon to amorphous silica leads to a stiffening of the material by removing the bending degrees of freedom of Si-O-Si bonds. This transition in mechanisms of stiffness, leads to a distinctly nonlinear behavior of the bulk and elastic modulus over the C/Si ratio. Experimental results do not contradict our findings, however dominant pore effects impede conclusive comparison.
Anton J. Bauer, Peter Friedrichs, Michael Krieger, Gerhard Pensl, Roland Rupp and Thomas Seyller
J. M. Knaup et al., "Elastic Properties of Dense Organosilicate Glasses Dependent on the C/Si Ratio", Materials Science Forum, Vols. 645-648, pp. 267-270, 2010