Investigation of Migration and Transformation of Self-Interstitial Atoms in 3C-SiC via DFT Calculations

First-principles calculations were carried out to investigate the stable and potential metastable structure of self-interstitial atoms (SIAs) in 3C-SiC. The most stable C and Si interstitials we obtained are Ci-C and Sii-Si split interstitials, respectively. In addition, a serious of metastable structures Ci-C (x = 0.63 ~ 0.81), Ci-C , Ci-Si , Sii-Si and Sii-Si have been observed. The migration and transformation of these SIAs were systematically studied. The minimum migration barrier for the full space rotation of C and Si interstitial are 0.49 eV and 0.73 eV, respectively. For the long-distance migration of SIAs, the minimum migration energy for C and Si interstitials is 0.71 eV and 0.73 eV, the corresponding migration paths are Ci-C(2 ‾5‾ 2) ↔ Ci-Si(1 1 6) ↔ Ci-C(‾5‾ 2 2), and Sii-Si ↔ SiTC ↔ Sii-Si .