Abstract
Amorphous silicon nitride is a model system for a covalently bound amorphous solid with a low atomic mobility where reasonable values of self-diffusivities are still lacking. We used neutron reflectometry on isotope enriched multilayers to determine nitrogen self-diffusivities ranging from to between 950 and 1250 °C. Time dependent diffusivities observed at 1150 °C indicate the presence of structural relaxation. For long annealing times (relaxed state) the diffusivities follow an Arrhenius law with an activation enthalpy of . The results are indicative of a direct diffusion mechanism without the involvement of thermal point defects.
- Received 24 October 2005
DOI:https://doi.org/10.1103/PhysRevLett.96.055901
©2006 American Physical Society