近水窗波段软X射线多层膜反射镜制备及性能
文献类型：学位论文
| 作者 | 邓淞文 |
| 学位类别 | 博士 |
| 答辩日期 | 2010 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 邵建达 |
| 关键词 | 软X射线多层膜 近水窗波段 反射率 结构 模拟退火算法 |
| 其他题名 | Preparation and property study of the soft X-ray reflector in the “near water window region” |
| 中文摘要 | 4.48nm处的近水窗波段软X射线多层膜反射元件与现代科学技术研究的前沿课题密切相关。它在天文学、生物样品的全息术、X射线激光以及同步辐射装置等方面都有非常重要的用途。本文围绕4.48nm处的近水窗波段软X射线多层膜反射镜开展了一系列的研究工作。 本文将间隔层元素吸收边附近的软X射线振荡反射率曲线和远离吸收边的硬X射线小角反射率谱线结合起来，提出了无损的多层膜结构精细分析的方法。基于此方法我们对本实验室磁控溅射设备制备的Ni/C，W/C和Cr/C体系进行了精细的分析，取得了很好的效果。通过分析我们综合各方面的因素认为Cr/C体系具有更好的本征特性和膜系结构。 分析了Cr/C多层膜体系中存在的缺陷，我们认为O元素的污染、中间层和粗糙度是主要的缺陷。我们认为O污染的出现以及层间元素的互扩散是导致光学常数偏离Henke常数的主要原因。随后通过计算和比较分析了我们制备的Cr/C膜系中存在的各种缺陷对于反射率的影响。我们发现中间薄层的出现实际上对反射率影响很小，而粗糙度如传统的认为的那样是对反射率影响最大的。O的污染实际上是由于我们的沉积系统本底真空不高导致的必然结果。它的出现对于反射率的影响接近了粗糙度，极大的降低了它的反射率而且由于光学常数的改变偏离了设计的工作波长或者工作角度。 探索了使用碳缓冲层平滑K9玻璃基底的工艺；随后制备了不同工艺条件的多层膜系统，优选了制备多层膜的工艺；在确定制备工艺之后，我们重新标定了Cr和C两种材料在超薄状态下的沉积速度。最后我们完成了薄膜制备、测试和分析。我们制备的膜系具有良好的周期结构和粗糙度，但是没有获得好的同步辐射结果，我们认为原因主要来自薄膜沉积设备不能达到要求、同步辐射光源质量不高和基片选择的过于粗糙。 使用模拟退火算法设计了近水窗波段顶部平坦型宽带和宽角的反射器。在设计波段4.473-4.488 nm，4.455-4.496 nm 和4.435-4.529 nm，正入射反射率达到了35.0%，24.2%和12.6%；对于入射角度范围44.85°- 45.16°，44.54°- 45.46°和 44.02°- 45.98°，s分量的平均反射率分别达到了39.7%，23.1% 和 13.0%。其中后两种宽角的膜系结构是当前磁控溅射技术可以完成制备的。 设计和编程了分子动力学模拟程序，模拟在Si的表面沉积C薄膜的过程。我们研究了单个C原子从入射到稳定的整个参数变化，随后我们模拟了C原子在光滑Si表面和粗糙Si表面沉积的过程，得出了C平滑基底的机理。 |
| 英文摘要 | Soft X-ray reflector working at 4.48nm-“near water window region” is closely related to the frontier of modern science and technology. It’s useful in astronomy, biological sample imaging, X-ray laser and synchrotron radiation facility. This dissertation carried out a series of research work centered on Soft X-ray reflector working at 4.48nm. This dissertation brought forward a non-destructive layer structure analysis method which combined soft X-ray resonant reflectivity and grazing incidence hard X-ray reflectivity together. Based on this method, we finely analysis the layer structure of the Ni/C，W/C and Cr/C multilayer system fabricated by the magnetron sputtering and got desirable results. After overall analyzing all aspect, we concluded that Cr/C multilayer system has better intrinsic properties and layer structure. Three kinds of defects (interlayer, rough interface and contaminant) were found in the Cr/C multilayer soft X-ray mirror and their impacts on the reflectivity at 4.48nm were analyzed. Chromium carbide was not found at the interface probably due to the blocking of the oxide’s formation. Due to the contaminant (O), the optical constants of C layer vary significantly compared with the slightly change of the Cr layer. The influence of thin interlayer on the reflectivity is relatively small and the rough interface can decrease the reflectivity dramatically. We find the contaminant can not only decrease the reflectivity a lot but also change the position of peak. We smoothed the K9 substrate using C films; optimized the parameters to fabricate the Cr/C multilayer; re-determined the deposition rate of the ultra thin Cr/C multilayer. At last, we deposited the reflector, test and analysis. Although we get good period structure and low roughness, the property didn’t achieve the standard we expected. We believed the deposition equipment, quality of the synchrotron radiation beam and rough substrate were the main reason. We optimized top-flat broad band (normal incidence) and broad angular (around quasi-Brewster angle) Cr/C non-periodic multilayer reflector. In the wavelength region 4.473-4.488 nm, 4.455-4.496 nm and 4.435-4.529 nm, mean theoretical normal incidence reflectivity can get 35.0%, 24.2% and 12.6% respectively by the top-flat broad band reflectors. In the grazing incidence angle region 44.85°-45.16°, 44.54°-45.46° and 44.02°-45.98°, mean s-component theoretical reflectivity at 4.48 nm can get 39.7%, 23.1% and 13.0% respectively by the top-flat broad angular reflectors. We designed molecular dynamic programming to simulate the process of C depositing onto the silicon. We studied parameter change of the single C atom from injection to stabilization. Then we simulated the deposition process on the smooth Si surface and rough surface and got deposition mechanism. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15295]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 邓淞文. 近水窗波段软X射线多层膜反射镜制备及性能[D]. 中国科学院上海光学精密机械研究所. 2010. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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