Release behavior of an interstitial helium atom from 3C-SiC(100) subsurface: A first-principles study

The annealing-promoted He release process in irradiated SiC remains unclear. Herein the atomistic release behavior of a He atom from 3C-SiC(100) subsurface is investigated by density functional theory calculations. The results show that the interstitial He atom in the 3C-SiC(100) subsurface tends to diffuse to the surface by overcoming a diffusion barrier of 0.72 eV, rather than to infiltrate into the slab interior, supporting a bulk-diffusion-limited mechanism for He release from SiC. The He atom can spontaneously diffuse on the 3C-SiC(100) surface, suggesting a retarding effect on He release from irradiated SiC. The results provide deeper insight into the release mechanism of He defects in irradiated SiC and are useful for improving defect recovery strategies.