Study of the recrystallization behaviors induced by annealing and irradiation on amorphous SiC

Silicon carbide and its derivatives are promising materials with potential applications in various types of nuclear reactors. To better understand their characteristics, this paper investigates the recrystallization behavior of amorphous SiC prepared through pre-irradiation using 800 keV Kr2+. Following different annealing processes, Raman spectra revealed that recrystallization happened beyond 873 K, and nearly complete recrystallization of the amorphous layer occurs at 1423 K. Afterward, in situ annealing and He+ irradiation experiments were conducted. The results indicate that the recrystallization progress is a layer-by-layer epitaxial regrowth on the amorphous–crystal interface under 873 K annealing, and the epitaxial recrystallization would slow down mainly due to the accumulation of defects and Kr atoms. However, under 30 keV He+ irradiation at 873 K, the interface continues to move. Moreover, when the irradiation dose rises, nanocrystals and helium bubbles appear simultaneously, growing in both size and density. The different recrystallization behaviors caused by irradiation and non-irradiation conditions could be explained by radiation-enhanced atomic diffusion, and helium bubbles are likely to be the by-products of nanocrystal formation. A possible explanation is proposed. This study provides insights into the practical application of amorphous silicon carbide in reactors and other irradiation environments.