荷能Xe 离子注入SiC 中缺陷和力学性能演化行为的研究
文献类型：学位论文
| 作者 | 李健健 |
| 答辩日期 | 2012-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 张崇宏 |
| 关键词 | 离子注入 缺陷演化 Hrxrd Raman光谱 纳米硬度 |
| 学位名称 | 硕士 |
| 学位专业 | 凝聚态物理 |
| 其他题名 | 纳米硬度 |
| 英文摘要 | /* Generator: eWebEditor */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0cm;margin-bottom:.0001pt;text-align:justify;text-justify:inter-ideograph;font-size:10.5pt;font-family:"Times New Roman";} div.Section1 {page:Section1;} Silicon carbide (SiC) possesses outstanding physical, chemical and electronic properties that make it very promising for applications in semiconductors, advanced nuclear reactors and nuclear waste technology. Studies on the accumulation of radiation damage and gaseous impuries in SiC are of primary importance. In the present work，the microstructure damage，defects accumulation and evolution，and mechanical properties of SiC irradiated by multiple-energy Xe ions were studies. Specimens of 6H-SiC were implanted with Xe ions with multiple kinetic energies ranging from 3.3 to 8 MeV at room temperature to obtain nearly uniform Xe concentrations, in the depth between 850 and 1800 nm, to 7.5, 30, 150 at.ppm, respectively. The irradiated specimens were subsequently thermally annealed under high vacuum at temperatures of 773, 1073 and 1373 K, respectively. The lattice damage and defect evolution were studied by high resolution x-ray diffraction spectrometry (HRXRD), Raman scattering spectroscopy, and transmission electron microscopy (TEM)，while changes in mechanical properties were analyzed by the nanoindentation measurement in the continue stiffness mode. In the specimen Xe-implanted to a concentration of 7.5 at.ppm Xe, HRXRD and Raman scattering results suggest that the irradiation damage mainly induce the lattice expansion in the implanted SiC, while TEM results show that the the implanted layer keeps crystalline state. The main species are point defects. Interstitial-type point defects are supposed to play a major role in the lattice expansion. Upon subsequent thermal annealing the strain relaxes gradually. The relaxation of the strain follows Arrhenius plot. The obtained apparent activation energy of strain relaxation (Ea=67±5 meV) is lower than the value of interstitial migration energy from theoretical calculations, possibly due to the migration of interstitial defects enhanced by the strain gradient. In the specimens implanted to 30 at.ppm and 150 at.ppm Xe， formation of amorphous layers is confirmed from Raman spectrum and TEM results. The buried amorphous layer is observed in the 30 at.ppm Xe implanted specimens, while the implanted region of the 150 at.ppm-Xe specimens has been completely amorphized from the specimen surface. HRXRD results show that the satellite peak near the main peak reappears after thermal annealing which may not be from the surface region but from a buried strain layer between the amorphous layer and the unperturbed bulk crystal. The strain value related to the satellite peak decreases with increasing annealing temperature and is independent of the ion fluence. In addition, Raman spectrum studies indicate that carbon-type defects begin to migrate at annealing temperatures from 773 to 1073 K, but Si-type defects diffuse obviously at a higher annealing temperature of 1373 K. The amorphization is ascribed to the observed volume swelling of the irradiated SiC.Microstructure changes due to irradiation can alter the mechanical properties. The nanohardness value of the specimen implanted to 7.5 at.ppm exceeds that of virgin SiC, whereas it is opposite in the cases of 30 at.ppm and 150 at.ppm Xe implantation due to the formation of amorphous regions. When complete amorphization is reached, the hardness value decreases strongly by about 45%, which is in agreement with previous work. |
| 源URL | [http://ir.impcas.ac.cn/handle/113462/17601]  |
| 专题 | 近代物理研究所_材料研究中心 近代物理研究所_能源材料研究组 |
| 作者单位 | 中国科学院近代物理研究所 |
| 推荐引用方式 GB/T 7714 | 李健健. 荷能Xe 离子注入SiC 中缺陷和力学性能演化行为的研究[D]. 北京. 中国科学院研究生院. 2012. |
入库方式： OAI收割
来源：近代物理研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。