碳化硅的化学气相沉积研究
文献类型：学位论文
| 作者 | 杨艳 |
| 学位类别 | 博士 |
| 答辩日期 | 2010-05-10 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 张伟刚 |
| 关键词 | 化学气相沉积 SiC 沉积动力学 防氧化涂层 |
| 其他题名 | Study on chemical vapor deposition of silicon carbide |
| 学位专业 | 化学工程 |
| 中文摘要 | 通过化学气相沉积技术制备的碳化硅（CVD SiC）具有许多优异的性能，可作为高温半导体、硬质耐磨涂层和抗高温氧化涂层等重要材料使用。本文采用等温等压化学气相沉积技术，分别以CH3SiCl3（MTS，Methyltrichlorosilane）-H2和SiCl4-CH4-H2为气源，在800~1100 ℃的沉积温度范围和一个大气压实验条件下，在堇青石陶瓷基体上制备了SiC薄膜材料，研究了两种气源沉积SiC的化学气相沉积速率。利用分析测试技术对所制备的CVD SiC薄膜的结构和组成进行了表征。研究发现H2/MTS摩尔比、H2/SiCl4摩尔比、沉积温度、比表面积以及反应室内不同位置等工艺参数对SiC的沉积速率、沉积薄膜的结构和生长形貌有着重要的影响。研究表明：化学气相沉积是一个复杂的气固相反应过程，SiC是气相反应和表面反应相互竞争的结果。该过程可以分为低温和高温两个截然不同的化学过程，并且沉积速率并不总是随温度的升高而增大。以CH3SiCl3-H2为气源时，低温下主要发生Si与SiC的共沉积，高温下发生SiC的化学气相沉积。同时氢气浓度和基体比表面积对沉积速率均有重要影响。由SiCl4-CH4-H2生成SiC的化学气相沉积过程，在低温沉积受表面反应控制；高温沉积是由大的气相分子的形成所控制，其表观活化能约为152 kJ·mol-1。 |
| 英文摘要 | Silicon carbide (SiC) prepared by chemical vapor deposition (CVD) exhibits excellent properties such as high hardness, chemical inertness and thermal stability, etc. Therefore, it has been used as high temperature semiconductor, wear resistance hard coating and high temperature oxidation resistance coating. Thin films of SiC deposited on cordierite substrates were prepared from precursors of CH3SiCl3 (MTS, Methyltrichlorosilane)-H2 and SiCl4-CH4-H2 gaseous sources respectively using isothermal isobaric chemical vapor deposition at the temperatures ranging from 800 ℃ to 1100 ℃, the pressure is about 101.3 kPa. Deposition rates of SiC from MTS-H2 and SiCl4-CH4-H2 gaseous sources were studied respectively. The as-deposited thin film was characterized with scanning electron microscope (SEM), X-ray diffraction (XRD), Raman micro-spectrum (RS), high-resolution transmission electron microscopy (HRTEM) and EDS elementary analysis. The results have shown that CVD of SiC is a complex gas-solid phases reaction process and is the competent result between homogeneous gas phase reactions and heterogeneous surface reactions. This process includes two different chemical reaction processes: low temperature and high temperature process. In the kinetic regime of chemical vapor deposition, the deposition rate doesn’t increase with the increasing of temperature all the time. Co-deposition of silicon and silicon carbide occurs at lower temperature regime and the deposition of SiC occurs at higher temperature from CH3SiCl3-H2 gaseous source only. Both of the concentration of hydrogen and the ratio of substrate area to the volume exhibit important impact on the deposition rate and the stoichiometry of the deposits. The deposition kinetics of SiC from SiCl4-CH4-H2 gaseous source at lower temperature is controlled by surface reactions and deposition kinetics at higher temperature is controlled by the formation of reactive gas phase species, whose apparent activation energy is about 152 kJ·mol-1. The micro-structural investigation indicates that the thin film of the SiC deposited from CH3SiCl3-H2 source at 1100 ℃ consists of pure β-SiC phase and the surface morphology of SiC thin film shows a hexagonal structure which is significantly different from that of SiC deposited from SiCl4-CH4-H2 source. Hexagonal structure reveals that (111) plane of β-SiC is the preferred orientation in the XRD pattern. However, the thin film deposited from SiCl4-CH4-H2 gaseous source at 1100 ℃ still contains trace of amorphous carbon. Therefore, surface morphology of SiC from this precursor shows semi-sphere structure which was grown in layer accumulation way, and can be changed to loose cluster along the substrate length, meanwhile the particles size in the film becomes larger. In most cases, the average size of hexagonal shaped particles deposited from CH3SiCl3-H2 gaseous source is bigger than that deposited from SiCl4-CH4-H2. Chemical vapor deposited SiC film obtained in the study was used for the anti-oxidation coatings. The anti-oxidation coating for carbon/carbon composites is obtained using pack cementation technique and pack cementation/CVD technique, respectively. The results show that coating obtained from the pack cementation/CVD technique is even and compact which forms dense covering of the pack. It is indicated from the experiments that the external CVD SiC coating can effectively prevent the diffusion of oxgen into the internal carbon/carbon composites because of the sealing the pores and cracks in the pack. Therefore, the anti-oxidation property of carbon/carbon composites is highly improved at high temperatures, which can be confirmed from the correlation of oxidation weight loss and temperature. |
| 语种 | 中文 |
| 公开日期 | 2013-09-22 |
| 页码 | 187 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1635]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 杨艳. 碳化硅的化学气相沉积研究[D]. 中国科学院研究生院. 2010. |
入库方式： OAI收割
来源：过程工程研究所
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