摘要
Radiation-induced defect annealing in He<sup>+</sup> ion-implanted 4H-SiC via H<sup>+</sup> ion irradiation is investigated by Raman spectroscopy. There are 4H-SiC wafers irradiated with 230 keV He<sup>+</sup> ions with fluences ranging from cm<sup>−2</sup> to cm<sup>−2</sup> at room temperature. The post-implantation samples are irradiated by 260 keV H<sup>+</sup> ions at a fluence of cm<sup>−2</sup> 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 966 cm<sup>−1</sup>, which is assigned to 3C-SiC LO () phonon, is found in the He-implanted sample with a fluence of cm<sup>−2</sup> followed by H irradiation. However, for the He-implanted sample with a fluence of cm<sup>−2</sup> 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.
Radiation-induced defect annealing in He<sup>+</sup> ion-implanted 4H-SiC via H<sup>+</sup> ion irradiation is investigated by Raman spectroscopy. There are 4H-SiC wafers irradiated with 230 keV He<sup>+</sup> ions with fluences ranging from cm<sup>−2</sup> to cm<sup>−2</sup> at room temperature. The post-implantation samples are irradiated by 260 keV H<sup>+</sup> ions at a fluence of cm<sup>−2</sup> 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 966 cm<sup>−1</sup>, which is assigned to 3C-SiC LO () phonon, is found in the He-implanted sample with a fluence of cm<sup>−2</sup> followed by H irradiation. However, for the He-implanted sample with a fluence of cm<sup>−2</sup> 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.
基金
Supported by the National Natural Science Foundation of China under Grant Nos 11005130,11475229 and 91026002
the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDA03010301
