Atomic-scale assessment of the crystallization onset in silicon carbonitride

摘要

Within the present study, atomic-scale electron microscopy investigation on the crystallization behavior of polysilykarbodiimide-derived SiCN was performed. The as-prepared SiCN sample was found to be homogeneous and consisted of amorphous silicon nitride nano-domains dispersed within an amorphous, highly entangled graphene-like carbon matrix. Annealing of the sample at 1400 degrees C induced a slight increase of the ordering of the carbon phase. Additionally, the crystallization onset of the silicon nitride has been observed for the first time. In the sample annealed at 1400 degrees C small nano-clusters with average sizes of 0.8, 1.5 and 2.1 nm (consisting of 30, 180 and 570 atoms, respectively; corresponding to Si12N18, SinNiog and Si228N342) were imaged and assigned to a-silicon nitride. The crystallization of the amorphous silicon nitride phase into alpha-Si3N4 is thought to occur via diffusion of Si and N, which rely on the presence of large number of dangling bonds in the amorphous SiCN sample. (C) 2015 Elsevier Ltd. All rights reserved.