2005 Volume 46 Issue 3 Pages 552-556
The elucidation of the trapping and detrapping mechanisms of hydrogen isotopes in SiC is one of the most critical issues for future fusion reactors if SiC is used as the first wall and structure material. In this study, 1 keV deuterium (D2+) ions were implanted into SiC and the chemical states of C and Si were evaluated by X-ray photoelectron spectroscopy (XPS). The deuterium desorption and retention were also analyzed by thermal desorption spectroscopy (TDS). The deuterium desorption behavior for SiC was compared to that for Si and graphite, and it was found that deuterium is preferentially trapped by C and, after the saturation of the C-D bond, it is trapped by Si in SiC. Deuterium desorption was found to consist of two stages, namely deuterium desorptions bound to Si and C. Their trapping mechanisms were influenced by the damaged structures produced by the D2+ ion implantation. Finally, deuterium retention in SiC at temperatures above 700 K was higher than that in graphite, indicating that tritium retention in SiC may be high compared to that in graphite during plasma operation.
