Radiation-induced defect annealing in He+ ion-implanted 4H-SiC via H+ ion irradiation is investigated by Raman spectroscopy.There are 4H-SiC wafers irradiated with 230 keV He+ ions with fluences ranging from 5.0× 1015 cm-2 to 2.0 × 1016 cm-2 at room temperature.The post-implantation samples are irradiated by 260keV H+ ions at a fluence of 5.0 × 1015 cm-2 at room temperature.The intensities of Raman lines decrease after He implantation,while they increase after H irradiation.The experimental results present that the magnitude of Raman line increment is related to the concentration of pre-existing defects formed by He implantation.A strong new peak located near 966cm-1,which is assigned to 3C-SiC LO (T) phonon,is found in the He-implanted sample with a fluence of 5.0 × 1015 cn-2 followed by H irradiation.However,for the He-implanted sample with a fluence of 2.0 × 1016 cm 2 followed by H irradiation,no 3C-SiC phonon vibrations are found.The detailed reason for H irradiation-induced phase transformation in the He-implanted 4H-SiC is discussed.