Influence of CH{sub 2} content and network defects on the elastic properties of organosilicate glasses

Journal Article · Tue Feb 01 00:00:00 EST 2011 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.83.054204· OSTI ID:21538110

Knaup, Jan M ^[1]; Han, Li; Vlassak, Joost J ^[2]; Kaxiras, Efthimios ^[1]

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1. Institute of Materials Science, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)
2. School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States)

Organosilicate glasses (OSGs) are used as low-k intermetal dielectrics for advanced integrated circuits. In this application, the material must fulfill two conflicting requirements: It has to have low density to reduce the dielectric constant while being sufficiently mechanically stable to withstand thermomechanical and other stresses during subsequent steps of integrated circuit manufacture. Recent experimental advances in improving the mechanical and electrical properties of these materials have not yet been systematically studied theoretically at the ab initio level due to the large model sizes necessary to realistically describe amorphous materials. In this paper we employ the density-functional-based tight-binding method to achieve an accurate description of OSG properties at different compositions. We analyze the influence of composition and local network defects on the density and bulk modulus of nonporous OSG. We find that the dependence of density and that of mechanical stiffness on chemical composition are of different natures. This difference is traced to a transition between mechanisms of elastic deformation in silica glass and in silicon hydrocarbide, which is also the reason for the two materials' different sensitivities to network defects.

• OSTI ID: 21538110
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 83, Issue 5; Other Information: DOI: 10.1103/PhysRevB.83.054204; (c) 2011 American Institute of Physics; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL DEFECTS
DEFORMATION
DENSITY
DENSITY FUNCTIONAL METHOD
DIELECTRIC MATERIALS
ELASTICITY
FLEXIBILITY
GLASS
ORGANIC COMPOUNDS
PERMITTIVITY
SENSITIVITY
SILICATES
SILICON
CALCULATION METHODS
CRYSTAL STRUCTURE
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
ELEMENTS
MATERIALS
MECHANICAL PROPERTIES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SEMIMETALS
SILICON COMPOUNDS
TENSILE PROPERTIES
VARIATIONAL METHODS