Crystalline-to-amorphous transition in silicon carbide under neutron irradiation

We have investigated the neutron-induced amorphization in silicon carbide (SiC) film using molecular dynamics (MD) simulations with a modified Tersoff potential. The crystalline-to-amorphous (c–a) transition occurs at about 0.27 dpa along with a structural relaxation, indicating that the amorphization mechanism of neutron-irradiated 3C–SiC is homogeneous. The amorphization level will further be improved during more irradiation, which could be deduced from the increase of C–C bonds and decrease of C–Si bonds after c–a transition. The point defects tend to accumulate in defect-rich areas with C-depleted regions in the core and C-rich regions in the boundary. Such defect-rich areas caused by the displacement spikes results in the local inhomogeneity of C and Si atom distribution in the system, which will enhance the driving force for c–a transition based on thermodynamics. Evidences suggest that the displacement spike plays an important role in amorphization of 3C–SiC.

►The mechanism of neutron irradiation induced amorphization of 3C-SiC is homogenous in atomic level. ► A further structure relaxation occurs after irradiation-induced crystalline-to-amorphization. ► The defect-rich areas caused by the displacement spike play an important role in amorphization of 3C-SiC.