A comparison study of mechanical change and chemical disorder in 4H-SiC irradiated with Si5+ and He2+ at room temperature

The effects of ion mass on lattice disorder of 4H-SiC irradiated with Si and He ions at room temperature to doses of 0.04 displace per atoms (dpa) to 4.0 dpa were investigated by nano-hardness and Raman spectroscopy. The changes in mechanical property and chemical disorder after Si and He irradiation were compared. “Pop-in” phenomena were observed in the profile of load vs. penetration depth before and after ion irradiation. The profile of hardness value in the damaged layer exhibited “M” shape for He irradiation, while it decreased monotonously with increasing Si dose. The hardness value for Si irradiation to a dose of 0.08 dpa was almost equal to the value of He irradiation as high as 0.4 dpa. The Raman intensity of typical scattering peaks showed that it was smaller after Si irradiation than after He irradiation at the same dose. The possible reasons of more survival lattice defects in the Si-irradiated 4H-SiC are discussed.