Damage production in silicon carbide by dual ion beams irradiation

Abstract

Lattice damage and evolution in single crystalline 6H-SiC under Si + He successively dual ion beams irradiation is studied by using Raman spectroscopy, high resolution X-ray diffraction (HRXRD) and nano-indentation tests. Single Si and He ion irradiations are also performed for the comparison. The results of Raman spectra reveal that the damage level increases with the fluence. A normal strain profile along the ion path is generated due to ion irradiation induced dilation of lattices, contributing mainly by interstitial related defects. Moreover, Si and He ion implantation produced different types of defects. The damage and chemical bonding states are significantly changed after He atoms implanted in Si pre-irradiated samples. Si + He dual ion irradiations increase the damage level further, resulting in changes of the damage states because of complex defects interactions. The nano-hardness of irradiated SiC is combined results of hardening effects of some kinds of defects and the breakdown of covalent-bonds. The mechanical properties present significant differences between single Si, He and Si + He successively dual ion beam irradiations, due to defects evolution during the irradiation process.