Microstructure of Hydrogen-Implanted Polycrystalline \alpha-SiC after Annealing

Microstructural evolution in H-implanted polycrystalline \alpha-SiC upon thermal annealing at temperature 1100^\circC is studied. After annealing, the samples are examined via cross-sectional transmission electron microscopy (XTEM) analysis. H_2 gas bubbles are formed during H implantation and some H_2 molecules are released from the bubble to form cavities during thermal annealing. The distribution and size of the observed cavities are related to the implantation fluence. The results are compared to H implanted single crystal SiC and He implanted polycrystalline \alpha-SiC. The possible reasons are discussed.