Dose Dependence of Recrystallization Processes in Amorphous SiC

概要

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Ion-beam-induced amorphous layers of silicon carbide (SiC) as well as their recrystallized layers have been characterized by transmission electron microscopy (TEM). Single crystals of 6H–SiC with the (0001) orientation were irradiated with 150 keV Xe ions to fluences of $10^{15}$ and $10^{16}$/cm2, followed by thermal annealing at 940°C. Full recrystallizations took place in both specimens. Electron diffraction patterns and bright-field TEM images revealed that full epitaxial recrystallization occurred in the specimen implanted with $10^{15}$ Xe ions, while both epitaxial recrystallization and the occurrence of the cubic phase of SiC (3C–SiC) were observed in the specimen implanted with $10^{16}$/cm2 Xe ions. This is attributed to the difference in amorphous structures between the $10^{15}$ and $10^{16}$ Xe/cm2 implanted samples: the former shows a greater chemical short-range order in the amorphous state than the latter, and the chemical short-range order deteriorates with increasing ion dose. In addition, a higher Xe impurity concentration is also considered to be associated with the occurrence of 3C–SiC in a high-dose sample.
2005-08-15