Abstract

The ion-beam-induced crystalline-to-amorphous phase transition in single crystal ( 6 H) α -SiC has been studied as a function of irradiation temperature. The evolution of the amorphous state has been followed in situ by transmission electron microscopy in specimens irradiated with 0.8 MeV Ne + , 1.0 MeV Ar + , and 1.5 MeV Xe + ions over the temperature range from 20 to 475 K. The threshold displacement dose for complete amorphization in α -SiC at 20 K is 0.30 dpa (damage energy=15 eV atom −1 ). The dose for complete amorphization increases with temperature due to simultaneous recovery processes that can be adequately modeled in terms of a single-activated process. The critical temperature, above which amorphization does not occur, increases with particle mass and saturates at about 500 K. Single crystals of α -SiC with [0001] orientation have also been irradiated at 300 K with 360 keV Ar 2+ ions at an incident angle of 25° over fluences ranging from 1 to 8 Ar 2+ ions nm −2 . The damage accumulation in these samples has been characterized ex situ by Rutherford backscattering spectrometry–channeling (RBS/C) along the [0001] direction, Raman spectroscopy, cross-sectional transmission electron microscopy (XTEM), and mechanical microprobe measurements.

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