【作者】 王鸿翔；

【导师】 左敦稳；

【作者基本信息】 南京航空航天大学 ， 机械制造及其自动化， 2010， 博士

【摘要】 化学气相沉积(Chemical Vapour Deposition,CVD)金刚石具有优异的光学性能。近年来,金刚石涂层作为红外窗口增透或者保护涂层的应用成为人们关注的热点。为深入开展红外窗口金刚石涂层的应用基础研究并推动红外窗口金刚石涂层的产业化进程,本文从红外窗口金刚石涂层沉积设备的研制、金刚石涂层的透波及增透机理、涂层制备工艺、涂层的透波性能及膜/基结合性能等方面开展深入研究,分析各种因素对金刚石涂层红外透射率以及膜/基结合性能的影响,为红外窗口金刚石涂层产业化应用奠定基础。本文主要开展的研究工作如下:1.分析了金刚石沉积过程中反应室内衬底的热交换过程,建立了电子辅助化学气相沉积(Electron-Assisted CVD,EACVD)系统在衬底作无急回特性摆动时的衬底温度场动态模型,根据金刚石成膜过程中对衬底温度的工艺要求,对影响衬底温度场的热丝参数及衬底摆动参数进行了优化设计。根据EACVD系统的几何特点和工艺参数建立了该系统的三维流场有限元模型,利用该模型对摆动衬底表面的流场进行了模拟计算,研究了衬底温度及摆动周期、热丝参数、进气口参数对衬底表面流场均匀性的影响。2.在衬底温度场、空间流场仿真的基础上,针对传统多点测温以及现有EACVD设备所存在的一些问题,提出了带摆动衬底工作台的EACVD一体化系统的设计思路,实现系统的一体化、小型化,并满足制备红外窗口金刚石涂层的需要。多点测温实验以及金刚石涂层的沉积实验的结果表明,设备运行稳定,衬底温度场和空间流场可控,完全满足设计要求。3.对红外光学系统的透波、增透机理进行了分析,建立了红外窗口和金刚石涂层组成的膜系的透射率模型,根据透射率模型详细分析了影响膜系透射率的主要因素,为制备高质量、高透射率的红外窗口金刚石涂层提供理论指导。4.在单晶硅衬底上开展了微米及纳米金刚石透波涂层制备工艺的实验研究,对实验制备机理和工艺过程中的关键问题进行了深入的探讨和分析研究。使用Raman、场发射SEM、XRD、傅立叶红外光谱仪和三维形貌仪等现代理化手段对金刚石涂层的微结构和红外透射率进行表征。得到了工艺参数对金刚石涂层生长以及红外透射率的影响规律。结果表明,即使在最优工艺参数下制备的微米及纳米金刚石涂层在1000 cm-1~4000 cm-1波段范围内,增透效果不很显著,最高红外透射率低于50%,不能满足红外窗口涂层的应用要求。5.在微米及纳米金刚石涂层制备的基础上分别采用原位沉积法和交替沉积法进行金刚石红外透波复合涂层的制备研究,结果表明,采用交替沉积法制备的金刚石涂层具有较高的红外透射率,在1000 cm-1~4000 cm-1波段范围内最大透射率达62%,增透率达80%。研究了红外窗口金刚石透波涂层的膜/基结合性能,分析了不同工艺条件对金刚石涂层膜/基结合性能的影响,研究结果表明,采用交替沉积法制备的金刚石红外透波复合涂层具有较高的膜/基结合性能。更多还原

【Abstract】 Chemical vapor deposited (CVD) diamond film has the outstanding optical property. At present, diamond used for antireflection coating or protective coating in infrared windows becomes the hotspot. To develop the basic research for application of diamond coating for infrared windows and impel its industrialization process, study is carried out in this dissertation. The CVD deposition system, microwave-transparent mechanism, preparation technology, mechanical property and binding ability of the diamond coating are investigated in detail. To study how the factors influence the performance of diamond, modern analytical methods are carried out to analyze and evaluate the surface topography, microstructure and infrared transmittance. All the results of this research lay the foundation for the diamond coating’s industrial production application in infrared windows.The main work and results obtained in this dissertation are as follows:1. Base on heat transfer theory and Energy conservation law, heat exchange process of electron assisted chemical vapor deposition(EACVD)system was analyzed, then the dynamic model of EACVD system was set up when the substrate sways without quick-return characteristics. To satisfy the requirement of temperature for diamond deposition, filament parameters and substrate swing parameters were optimized. Base on the geometric characteristics and process parameters, three-dimension finite element model of the flow field of EACVD was set up, and then the influence of substrate temperature, hunting period, filament parameters and inlet parameter in the uniformity of substrate surface was studied.2. Based on the finite element analysis of temperature and flow field, some parts of the EACVD system including the mechanical system and control system were redesigned and improved to meet the need for diamond deposition used in infrared windows. Then performance of the EACVD was studied by multi-point temperature measuring test and diamond deposition experiment. Results showed optimized system provides uniform temperature and flow field which was good for diamond deposition.3. Study of the microwave-transparent mechanism of infrared optical system was carried out, the transmittance model made of infrared windows and diamond film was set up to analyzed the optical antireflection mechanism and the relationship between reflectivity and refractive index of infrared windows and thickness of diamond film. Major factors influencing the transmittance were found out to provide the theoretical direction for preparation of high quality diamond coating. 4. Experimental study on the preparation of Nano-crystalline diamond (NCD) film and Micro-crystalline diamond (MCD) film was carried out on mono-crystalline silicon, and the key technologies in the process were investigated. The microstructure and infrared transmittance were characterized by Raman, SEM, XRD, Fourier transform infrared spectrometer (FTIR) and Three-dimensional topography instrμment. By studying the influence rules of process parameters on infrared transmittance, optimized parameters were obtained. The results showed that the highest infrared transmittivity of the MCD and NCD was below 50% at the range of 1000 cm-1 and 4000 cm-1.The diamond coating can not meet the demands of infrared window application.5. Base on the preparation of NCD and MCD, study of the composite diamond films was carried out by In situ deposition method and Alternating deposition method. The results showed that the diamond film obtained using alternating deposition method had high infrared transmittance. At the range of 1000cm-1 and 4000cm-1, the maximum transmission rate and antireflective rate arrived at 62% and 80% respectively. Binding ability of the diamond coating were analyzed to study how the process parameters influence the performance, and the results showed that the diamond film obtained using alternating deposition method had good binding ability. .更多还原