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 ke...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.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11005130,11475229 and 91026002the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDA03010301
文摘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.
文摘以残余氯质量分数约1 000×10^(-6)的二甲基二氯硅烷水解物为原料,采用离心萃取机作为强化水解物中残余氯去除效果的装置,研究了水洗温度、叶轮直径、水解物与水的体积比、水解物进料流量等对残余氯去除效果的影响。结果表明,在水洗温度95℃、叶轮直径50 mm、水解物与水的体积比0.3∶1、水解物进料量90 m L/min的条件下,采用离心萃取机通过一次水洗可将水解物中残余氯质量分数控制在3×10^(-6)以内。