Molecular Dynamics Simulations of Amorphous Si–C–N Ceramics: Composition Dependence of the Atomic Structure

We have performed classical molecular dynamics simulations of amorphous Si–C–N materials. The dependence of the local order and of the microstructure on the chemical composition was investigated. Our simulations show that for a stoichiometric nitrogen/silicon ratio equal to or higher than 4/3, the amorphous ceramic separates into different amorphous domains, namely C‐rich, SiN‐rich, and SiC‐rich phases. Below this ratio, the material is composed of mixed structures, homogeneously spread within the material. For a very particular composition range, we found that carbon atoms crystallize into monoatomic graphitic layers surrounding the SiN‐rich domains.