Microstructure of heavily neutron-irradiated SiC after annealing up to 1500°C

Lattice damage and nanohardness in 6H–SiC implanted with multiple-energy Xe ions

“…Even at 1373 K, the strain remains, indicating that the defects (mainly interstitial-type) leading to the lattice expansion [8] are still subsistent. This is in agreement with previous results which demonstrate that the interstitial-type point defects were not recovered completely on annealing until 1523 K though the migration of interstitials begins above 773-873 K [18]. The formation of clusters of point defects and Xe-vacancy complexes during the implantation or annealing process is supposed to limit the recombination of point defects.…”

“…4. However, the activation energy related to interstitial migration energy is lower than theoretical calculation (0.2-1.6 eV) [18]. Previous studies show that the strain gradient and temperature enhance the migration of interstitials [8] and may lower the migration energy.…”

“…The strain relaxation behavior upon subsequent annealing due to the recombination of point defects is related to the different energies of migration of point defects (including interstitials and vacancies). Recently it was shown that vacancy-type defects with rather high energies of migration (silicon vacancies: 3.2-3.6 eV, carbon vacancies: 3.5-5.2 eV) begin to diffuse above 1273-1473 K [18,19] (1273-1373 K under neutron irradiation [18], 1273-1473 K under He irradiation [19]) leading to the formation of voids. So the interstitial-type defects with low energies of migration may play main roles in the strain relaxation between the annealing temperature regions 773-1373 K via their fast migration and recombination with immobile vacancies.…”

Transmission electron microscopy investigations of bubble formation in He-implanted polycrystalline SiC

“…The result demonstrates that C concentration significantly increased at GBs, whereas Si concentration did not change, indicating a large number of implantation-induced C interstitials trapped by GBs. Sawabe et al [23] mentioned the migration energies of Si vacancies of 3.2e3.6 eV and C vacancies of 3.5e5.2 eV, depending on the charge state [24]. However, Gao et al mentioned the migration energies of C interstitials and Si interstitials of 0.74 eV and 1.53 eV [25], respectively.…”

Swelling and stacking fault formation in helium implanted SiC

“…Even if the point defect concentration decreases with increasing T i , their annihilation was expected to start near the irradiation temperature as reported in neutron irradiated SiC [20,21]. The stability of the step height with annealing is thus related to the implantation-induced strain gradient or to the presence of helium.…”