Effects of He on the recrystallization and Mg diffusion in Mg ion implanted CVD-SiC

In the present study, CVD-SiC samples were implanted with 50 keV Mg ions and co-implanted with 30 keV He ions and 50 keV Mg ions at room temperature, and then annealed at 1573 K for 20 h. The recrystallization and Mg diffusion behavior after annealing were characterized and analyzed. ToF-SIMS profiles indicated that Mg diffused faster in the Mg only implanted sample than in the He and Mg co-implanted sample. TEM results showed that He atoms diffused toward the surface regions with high damage to form He bubbles, which aided the recrystallization of the amorphous layer. Calculations by Mean Square Displacement (MSD) method based on MD simulation prove that the diffusion coefficient of Mg in the amorphous SiC is much higher than that in the crystal SiC. These results indicated that the accelerated recrystallization by He bubbles and themselves were responsible for inhibiting the diffusion of Mg in SiC.