中文摘要：

以4H-SiC为研究对象,在800℃下,用24keV的H^＋和30keV的He^＋分别进行H^＋单束、He^＋单束、先H^＋后He^＋双束和先He^＋后H^＋双束辐照,并利用原子力显微镜（AFM）研究辐照对4H-SiC表面形貌的影响.实验表明：H^＋辐照的样品表面出现直径平均约为8μm的大凸起,He^＋辐照的样品表面则产生了均匀的纳米尺寸的小凸起;H^＋辐照在材料表面产生的大凸起在辐照He^＋后消失;而He^＋预辐照之后再进行H^＋辐照,材料表面不会产生大的凸起,并结合X射线衍射（XRD）数据对这种氢氦协同效应进行了解释.结论表明,He^＋预辐照对凸起的形成有抑制作用,He^＋后辐照则对已产生的凸起有抛光作用.

英文摘要：

Single and sequential irradiations of 24 keV H^＋ and 30 keV He^＋ were performed at 800℃ to investigate the effects of irradiations on surface topography of 4H SiC by using atomic force microscope （AFM）. The experimental results show that blisters with diameter of about 8μm were observed on H^＋-irradiated specimen while blisters with uniform nano-seale sizes were found on He^＋-irradiated one. Large blisters induced by H＋ pre-irradiation disappeared after He＋ post-irradiation, and no blister appeared after H^＋ post-irradiation with He^＋ pre-irradiation. The mechanisms behind the complex synergistic phenomena between H and He are discussed by combing with X-ray diffraction （XRD） data. Thus, it indicates that He^＋ pre-irradiation can inhibit H blisters formation, while He^＋ post irradiation can remove the blisters induced by H^＋ pre-irradiation.