Formation of nano-twinned 3C-SiC grains in Fe-implanted 6H-SiC after 1500-°C annealing*

A nano-twinned microstructure was found in amorphous SiC after high-temperature annealing. Grazing incidence x-ray diffraction, high-resolution transmission electron microscopy, and electron diffraction were performed to characterize the microstructure and phase transition in the recrystallization layer. After 1500 °C or 2-h annealing, 3C-SiC grains and numerous stacking faults on the {111} planes were visible. Some 3C-SiC grains have nano-twinned structure with {011} planes. Between the nano-twinned 3C-SiC grains, there is a stacking fault, indicating that the formation mechanisms of the nano-twinned structure are related to the disorder of Si atoms. The increase in the twin thickness with increasing annealing temperature demonstrates that the nano-twinned structure can sink for lattice defects, in order to improve the radiation tolerance of SiC.