Amorphization of SiC under radiation environments

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 300 keV xenon ions to a fluence of 10¹⁵ cm^-2 at cryogenic (120 K) and elevated (373 K) 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 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. (author)