The implantation of 2450ppm[at]He at room temperature resulted in the formation of He platelets with very uniform diameters of about 9nm. These remained constant upon annealing at up to 1270K. An estimate of the pressure in the platelets suggested the presence of solid He; even above room temperature. A narrow size distribution and limited growth of the platelets was attributed to their trapping by circular dislocation dipoles which formed close to their rim when they reached a critical size. Upon annealing at up to 1500K, the platelets disintegrated into disks of bubbles with interstitial-type dislocation loops attached to them. The total volumes of bubble and loop components in such complexes were found to be equal. This striking relationship was attributed to a transfer of matrix atoms, from the bubbles to the associated loops, via dislocation-core diffusion.

Evolution of Helium Platelets and Associated Dislocation Loops in α-SiC. J.Chen, P.Jung, H.Trinkaus: Physical Review Letters, 1999, 82[13], 2709-12