Effects of helium irradiation on chemical behavior of energetic deuterium in SiC

Structural changes of SiC caused by deuterium (D2+) and helium ion irradiation were studied with X-ray photoelectron spectroscopy (XPS) for ion energies in the range from 0.5 to 3.0 keV. Thermal desorption spectroscopy (TDS) measurements were performed to study the desorption processes from SiC surfaces pre-irradiated with deuterium and helium of 10 and 8.0 keV ion energy, respectively. For both ion species the range is approximately the same. The XPS experiments showed that the carbon concentration in the vicinity of the SiC surface was reduced owing to the helium irradiation. This suggests that carbon was selectively sputtered by the helium irradiation. In the TDS experiments, the D2 desorption was found to consist of three processes. The activation energy and the released amounts of deuterium for each peak were affected by helium pre-irradiation.