Diffusion Coefficients Predicting Facet-Dependent Crystallization in Amorphous Silicon Nitride

Amorphous silicon nitride is a common material in microelectronics devices, which acts as an insulating barrier. Extended annealing times at elevated temperature can initiate crystallization of alpha-Si3N4, which does not possess the same barrier properties. Molecular dynamics can resolve the fundamental mechanism for alpha-Si3N4 crystallization and the influence of local environments. We compare two interatomic potentials and conclude that these models predict structural features (e.g., angular distributions and densities) which span the range of experimental measurements. We confirmed these models reproduce experimental estimates of activation energy and leveraged these models to identify crystallization drivers. We conclude that near-Tg, facet-dependent silicon nitride crystal growth rates can be predicted directly by either bulk or interfacial diffusion properties.