Volume swelling of amorphous SiC during ion-beam irradiation

Relationships between chemical short-range order and volume swelling of amorphous silicon carbide (SiC) under radiation environments have been examined using energy-filtering transmission electron microscopy in combination with imaging plate techniques. Single crystals of 4H SiC with (0001) orientation were irradiated with 300keV xenon ions to a fluence of 1015cm-2 at cryogenic (120K) and elevated (373K) temperatures. A continuous amorphous layer was formed in both specimens, but the magnitude of their volume change was different: volume swelling becomes more pronounced with decreasing irradiation temperatures. From radial distribution function analyses, it was found that the amount of Si Si atomic pairs increases more rapidly than that of C C atomic pairs with the progress of chemical disordering. We discuss the ion-beam-induced swelling in amorphous SiC within the context of our results as well as previous observations.