Abstract
Silicon carbide (SiC) is one of the attractive nuclear structure materials in the future, because it has many outstanding properties like high melting point, good mechanical property at high temperature, small cross-section of absorbing neutron, and so on. In this thesis, using transmission electron microscopy (TEM) and synchrotron radiation based X ray diffraction (XRD) to discuss the microstructure change and swelling effect of ion implanted single crystal 3C-SiC. The material is the thin film CVD single crystal 3C-SiC with 1.1μm thickness. The experiment is seperated to 3 parts. The details are as following: The first part is the single beam irradiation with helium ion (He+). The implanted temperature is 800, 1000 and 1200℃. Using 175, 225 and 275 keV of He+ form a region that has 15000 or 45000 appmHe. This region is at 0.6 - 0.8μm from the sample surface. In the experiment of 15000 appm, the He bubbles will form at the stacking fault region at 800℃. when temperature up to 1000℃, bubbles appear not only at the stacking fault region but also at its near region. The bubble density is higher than the bubble density of 800℃. The bubbles appear in everywhere and the bubble size is increasing obviously at 1200℃. When dose up to 45000 appm, the bubble size and density are increasing, but the bubble appeared region is not affected by dose at the same implanted temperature. Besides, there is only 66% of implanted He atoms diffuse into the bubble at 15000 appm, 1200℃. When the dose increase, the percentage will also increase.However, the percentage of helium atoms diffuse into bubble does not reach 100% at 45000 appm, 1200℃. It suggest that the amount of defects caused by ion irradiation are less than implanted helium ion. In the second part, the single beam ion implantation up to 20 dpa with 2.9 MeV Si2+ at 40 and 200℃. The sample become amrophous at 40℃, but it is still crystalline at 200℃. The swelling is 7.7% at 40℃. Besides, using synchrotron radiation based XRD radial scanning to get the interplanar information of 200℃. The results find that the swelling is anisotropic, owing to the limitation of Si substrate. Besides, humps are found in Si(002) radial scan result, it may caused by the defect cluster. Also, the swelling which caused by each type of point defect was calculated. The last part is the dual beam implantation with 201, 467 keV He+ and 5.1MeV Si2+at 1000 - 1350℃. The average dose in implanted area is about 100 appmHe/ 1 dpa. In the statistic, the bubble density decrease, but the bubble size increase as temperature increasing. The increasing dose will cause bubble size and density become lager and denser. Besides, the bubble distribute in the irradiated region homogeneously. This result is defferent from the helium single beam obviously. At the last, compare the experimental statistics with many lectures.