Retention and replacement of hydrogen isotopes and isotope effect in SiC by H+ and D+ ion irradiation

The retention and isotope replacement behavior of hydrogen isotopes in SiC has been studied by means of the elastic recoil detection (ERD) technique. The protium ions or deuterium ions were implanted into SiC at room temperature up to almost the saturation. Successively, the ion source was switched to deuterium ions or protium ions and the samples were irradiated at the same fluence under the same experimental conditions, respectively. The mass balance equations were applied to analyze the retention curves and the curves of decay and uptake in the isotope replacement. The saturation concentrations of H and D have been found to be about 0.70 and 0.75, respectively. The detrapping cross sections of H and D implants by the D2+ and H2+ ion bombardments have been determined to be 3.2±0.3×10−22 m2/D+ and 2.6±0.2×10−22 m2/H+, respectively. The magnitude of these detrapping cross sections from SiC is as large as that from graphite. These isotope differences are discussed in terms of the elementary processes included in the mass balance equations.