量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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The evolution of He implantation-induced defects in polycrystalline α-SiC has been investigated by a combination of positron annihilation Doppler broadening spectroscopy (DBS) and transmission electron microscopy (TEM). Samples implanted at room temperature with 230 keV He+ ions to fluences of 1 × 1015, 5 × 1015 and 1 × 1016 ions/cm2 were isochronally annealed in vacuum at temperatures up to 1400 °C with a step of 100 °C. Excellent correlation between the calculated damage profile and the positron annihilation depth profile were obtained at low annealing temperatures, after considering the positron depth distribution given by so-called Makhovian profiles.
The DBS data from the peak region revealed a reasonable correlation between positron trapping at vacancy-type defects and the He-to-dpa ratio. Thermal annealing at 1400 °C resulted in the incomplete recovery of the microstructure, where large cavities distributed along grain boundaries in the damage peak region are surrounded by small agglomerations of (helium)vacancy-type defects.
Positron annihilation spectroscopy study of vacancy-type defects in He implanted polycrystalline alpha-SiC
