金刚石上不同晶体结构Y2O3膜性质与增透性能研究

目的研究不同晶体结构Y_2O_3薄膜的性质及其对金刚石增透性能的影响规律。方法采用反应磁控溅射的方法,通过控制氧氩比,在金刚石膜上制备立方与单斜两种不同晶体结构的Y_2O_3薄膜,随后系统研究两种Y_2O_3薄膜的性质与增透性能。结果在低氧氩比下获得了立方结构Y_2O_3薄膜,在高氧氩比下获得了单斜结构Y_2O_3薄膜,二者表面粗糙度分别为2.57、1.07nm。两种晶体结构均呈现出符合Y_2O_3原子配比的价态。立方和单斜结构的Y_2O_3薄膜硬度分别为17.4、12.6 GPa;弹性模量分别为248.1、214.6 GPa。双面镀制立方结构Y_2O_3薄膜后,金刚石膜在10.0μm透过率最大,达89.1%,增透24.5%;单斜结构Y_2O_3薄膜在7.4μm透过率最大,达90.4%,增透25.4%。结论通过控制氧氩比可以获得热力学稳定的立方Y_2O_3薄膜和亚稳态的单斜Y_2O_3薄膜。立方和单斜结构的Y_2O_3薄膜中O与Y原子价态均符合其化学计量比。立方结构Y_2O_3薄膜呈现出更高的硬度与弹性模量。两种结构对金刚石窗口均呈现出良好的增透效果。单斜结构Y_2O_3薄膜增透效果更佳与其较低的折射率有关,且相比于立方结构Y_2O_3薄膜,增透最佳值向低波长方向移动。     

金刚石自支撑膜衬底生长立方Y_2O_3薄膜的性能

采用射频磁控溅射法在抛光的CVD金刚石膜上制备了立方(222)择优取向的Y2O3薄膜,利用XRD,纳米力学探针,划痕仪,FTIR和TEM等手段研究了退火对Y2O3薄膜的结构、力学性能和红外透过率的影响及Y2O3的微观结构。结果表明:通过退火Y2O3薄膜的结晶程度增加,退火后的择优取向仍为立方相(222)晶面结构;薄膜的硬度降低而弹性模量升高,薄膜与金刚石的结合力增加;薄膜的红外透过率略有降低;薄膜为柱状晶结构并存在大量非晶态。     

CVD金刚石表面增透膜的研究进展

CVD金刚石膜因特有的物理化学性质,具有发展成为新一代光学材料的前景。但由于CVD金刚石膜自身局限性导致其理论透过率不到71%,在金刚石膜表面镀制增透膜,通过改变增透膜组成成分、显微组织和晶体结构,可有效地改善CVD金刚石膜自身理论透过率的问题。首先,介绍了CVD金刚石表面镀制单层增透膜增透原理,并总结了物理和化学气相沉积技术制备增透膜的优缺点。然后,重点综述了近年来CVD金刚石表面氮化物、金属氧化物和稀土金属氧化物等增透膜材料的研究进展,详细分析了增透膜制备参数、热处理工艺、衬底表面改性和掺杂工艺对增透膜整体组织和性能影响的规律。其中优化增透膜沉积温度、氧分压和热处理等工艺参数,是通过改变增透膜微观组织形貌以及晶体结构来提高其光学透过性能,而改变衬底表面结构能够通过改变增透膜与基体之间的成键方式来提升界面结合能力,而稀土元素掺杂方式是通过改变增透膜化学组成成分来改善增透膜的光学透过性能,并指出掺杂元素成型机理和影响机制。最后,展望了未来CVD金刚石表面增透膜的发展方向。     

CVD金刚石膜与常用红外光学材料抗砂蚀性能对比研究

目的通过分析CVD金刚石膜与几种常用红外光学窗口材料在砂蚀过程中形貌特征以及红外透过率的变化规律,获得CVD金刚石膜在砂蚀过程中的材料去除机制及抗砂蚀性能的关键因素。方法采用喷射式冲蚀磨损系统,对CVD金刚石膜及其他几种常见红外光学材料进行砂蚀性能测试。通过扫描电子显微镜对材料冲蚀后表面形貌进行观察,电子天平测量红外材料砂蚀率。采用红外光谱仪对砂蚀前后红外光学材料进行测量,评价其冲蚀前后的红外性能变化。结果 CVD金刚石膜抗砂蚀能力远高于Ge、ZnS、MgF_2以及石英玻璃。在设定测试条件下,仅经过6 s冲蚀,除CVD金刚石膜外,其余光学材料的红外透过性能下降40%~60%。而CVD金刚石经受240 min的相同条件冲蚀,其红外透过率仅下降9.5%,显示出极佳的抗砂蚀能力。结论 CVD金刚石膜的冲蚀过程主要是微裂纹形成及扩张连接导致材料流失。其他材料的冲蚀过程既有裂纹扩展,也有反复的切削、犁削,而后者是这些材料被冲蚀的主要原因。     

CVD单晶金刚石的制备及红外性能研究

利用微波等离子化学气相沉积法,以H₂/CH₄/N₂为混合气源,在CVD金刚石单晶基底上同质外延生长金刚石。在一定的甲烷浓度下,分析衬底温度对金刚石结晶质量及光学性能的影响。利用光学显微镜、扫描电子显微镜(SEM)表征金刚石单晶,得到金刚石单晶的样品颜色、内部缺陷、表面形貌等信息。对金刚石样品进行抛光处理后,使用红外傅里叶变换光谱仪对金刚石进行检测,得到红外波段的光学透过率。结果表明:在生长温度为930 ℃左右时金刚石的结晶质量最好,红外透过率最高,可达70%以上;略高或略低的温度均会降低其红外透过率,相对来说略高的温度下生长的金刚石结晶质量和红外性能优于低温下生长的金刚石的。N₂的掺杂会导致单晶带有棕褐色,生长速率显著变快,严重降低红外波段的光学性能。      

自支撑金刚石膜冲蚀磨损研究

在研制的高压气动冲蚀磨损实验系统中对自支撑金刚石膜(抛光和未抛光)的冲蚀磨损进行了研究.比较了冲蚀磨料(SiO2,Al2O3,SiC和玻璃珠)、冲蚀角度、冲蚀速度,以及冲蚀时间对冲蚀磨损率的影响.利用扫描电子显微镜(SEM)观察了冲蚀磨损后金刚石膜表面形貌,对其进行了Raman光谱分析,并测定了抛光金刚石薄膜红外透过率的变化.结果表明,随冲蚀磨料硬度、冲蚀角度以及冲蚀速度的增加,自支撑金刚石膜的冲蚀磨损率增加.由于抛光和未抛光的金刚石薄膜表面形貌的差异,使得它们的冲蚀磨损率随冲蚀时间的变化过程不同.Raman光谱检测结果显示,由于冲蚀作用,金刚石膜表面部分碳的键合类型发生改变.冲蚀磨损使得抛光金刚石薄膜红外透过率降低,采用180目SiC磨料,在134 m/s的速度下冲蚀4 h,红外透过率降低约20%.     

反应磁控溅射法制备Y2O3金刚石红外减反膜

采用纯钇(Y)金属靶,在氧 氩反应气氛中进行了Y2O3薄膜直流反应磁控溅射沉积.研究了工艺参数改变对薄膜的影响,选择较优的工艺在金刚石表面沉积符合光学厚度的薄膜,达到增透减反射效果.利用X射线光电子能谱(XPS)和扫描电子显微镜(SEM)研究了薄膜的组成和结构.利用X射线衍射仪(GIXRD)和椭偏仪(Ellipsometer)研究了不同衬底温度和热处理温度对氧化钇薄膜组织结构和光学性能的影响.采用傅立叶红外光谱仪(FTIR)检测了镀膜前后金刚石红外透过性能.研究发现Y2O3薄膜能够有效提高金刚石在8～12 μm的红外透过性能,在8 μm处最大增透可达21.8%,使金刚石红外透过率由66.4%提高到88.2%;在3～5 μm范围,双面镀制了Y2O3薄膜的金刚石平均透过率达64.9%,比没有镀膜的金刚石在该处的平均透过率54%高出10.9%.     

钽喷丝头表面覆加金刚石膜的研究

为改善钽喷丝头的品质，提高其硬度和耐碱腐蚀能力，利用热丝CVD制备不同粒径的金刚石薄膜，并通过对钽衬底的碳化处理，成功使之沉积于纯钽喷丝头表面，对纯钽喷丝头进行表面强化。通过场发射扫描电镜观察，大粒径金刚石薄膜有少量孔隙，小粒径金刚石薄膜细腻致密。硬度测试结果表明，金刚石薄膜钽喷丝头表面硬度达HV1000以上，远高于纯钽及其它工艺处理后的钽喷丝头。可纺性试验结果表明，其性能都达到或超过传统喷丝头，完全可以取代成本高昂的铂金喷丝头。     

大尺寸自支撑金刚石膜制备工艺及其红外透过性能研究

金刚石膜具有能够媲美单晶金刚石的优异物理化学性能,同时能够满足大尺寸的制备要求,是理想的红外窗口和芯片散热材料。本文采用微波等离子体化学气相沉积(MPCVD)设备,研究了不同沉积温度和甲烷浓度对金刚石膜沉积的影响,并通过SEM和Raman对其进行了表征分析。结果表明,当沉积温度过高时,会导致等离子体中的活性粒子能量增大,从而使金刚石晶粒变大;当沉积温度过低时,会造成金刚石膜中的石墨相含量增加。甲烷浓度的变化会引起环境中含碳基团浓度的变化,影响原子氢对石墨相的刻蚀作用,进而导致金刚石膜内石墨相含量的明显变化,影响金刚石膜质量。本文最终选用850℃的沉积温度和5.0%的甲烷浓度作为金刚石膜生长的沉积参数,通过长时间生长成功制备了直径76.2 mm的金刚石自支撑膜,并对其进行了XRD和红外透过性能测试。红外透过测试结果表明制备的自支撑金刚石膜在8～12μm波段透过率良好,平均透过率达到了56.8%。     

金刚石薄膜的双波段红外光学性能研究

本文针对红外光学材料对宽波段透过的要求,采用HFCVD法在硅基体上制备了红外增透的金刚石薄膜.设计了高红外透过率的膜系结构,探讨了基体处理方式、单面、双面涂层工艺和厚度对红外透过率的影响,并给出了相关的光谱测试结果和金刚石薄膜的微观形貌、结构表征.结果表明:双面涂层金刚石薄膜工艺具有优异的双波段红外性能,在3.0～5....     

硬质合金基体金刚石薄膜摩擦学性能研究的进展

硬质合金基体表面沉积金刚石薄膜可以提高其硬度和耐磨性,延长其使用寿命,有效保护和节约钨、钴等稀有金属。作为一种多晶膜,金刚石薄膜的摩擦系数直接影响了其在摩擦学领域的应用。对近年来硬质合金基体表面CVD金刚石薄膜的摩擦磨损性能的研究状况进行了阐述,分析了CVD金刚石薄膜在摩擦实验过程中的摩擦磨损机制,并对金刚石薄膜在摩擦学领域中的应用研究进行了展望。     

大孔径内孔表面金刚石薄膜涂层的制备

应用热丝化学气相沉积（HFCVD）工艺,并采用合适的衬底预处理方法和优化的工艺参数,在大孔径硬质合金内孔表面沉积了金刚石薄膜。分别采用SEM、EDS和喇曼光谱依次对衬底预处理前后内孔表面及沉积的金刚石薄膜进行了表征,并通过压痕实验评估了薄膜的附着强度。该压痕实验结果与薄膜的SEM及喇曼光谱表征的结果具有一致性。结果表明：采用合适的衬底预处理方法和优化的HFCVD工艺,可以在大孔径硬质合金内孔表面沉积高质量的金刚石薄膜。     

Time-modulated chemical vapor deposition of diamond films

This article investigates the role of substrate temperature in the deposition of diamond films using a newly developed time-modulated chemical vapor deposition (TMCVD) process. TMCVD was used to deposit polycrystalline diamond coatings onto silicon substrates using hot-filament chemical vapor deposition system. In this investigation, the effect of (a) substrate temperature and (b) methane (CH₄) content in the reactor on diamond film deposition was studied. The distinctive feature of the TMCVD process is that it time-modulates CH₄ flow into the reactor during the complete growth process. It was noted that the substrate temperature fluctuated during the CH₄ modulations, and this significantly affected some key properties of the deposited films. Two sets of samples have been prepared, in each of which there was one sample that was prepared while the substrate temperature fluctuated and the other sample, which was deposited while maintaining the substrate temperature, was fixed. To keep the substrate temperature constant, the filament power was varied accordingly. In this article, the findings are discussed in terms of the CH₄ content in the reactor and the substrate temperature. It was found that secondary nucleation occurred during the high timed CH₄ modulations. The as-deposited films were characterized for morphology, diamond-C phase purity, hardness, and surface roughness using scanning electron microscopy, Raman spectroscopy, Vickers hardness testing, and surface profilometry, respectively.     

SiC衬底金刚石薄膜的制备与性能表征

用热丝CVD法,以丙酮和氢气为碳源,在SiC衬底上沉积金刚石薄膜,提出了分步变参数沉积法制备超细晶粒金刚石复合薄膜的新工艺.结果表明,合理控制工艺条件的新工艺,对金刚石薄膜质量、形貌和粗糙度、薄膜与衬底间的附着力以及薄膜的摩擦系数有显著影响,金刚石薄膜的平均晶粒尺寸从3 μm减小到0.3 μm,拉曼特征峰显示超细晶粒金刚石薄膜特征,涂层附着力好,超细晶粒金刚石薄膜的表面粗糙度和摩擦系数值显著下降,对获取实用化的SiC在基体上沉积高附着强度、低粗糙度金刚石薄膜的新技术具有重要的意义.     

Effect of deposition temperature on properties of boron-doped diamond films on tungsten carbide substrate

Boron-doped diamond (BDD) films were deposited on the tungsten carbide substrates at different substrate temperatures ranging from 450 to 850 °C by hot filament chemical vapor deposition (HFCVD) method. The effect of deposition temperature on the properties of the boron-doped diamond films on tungsten carbide substrate was investigated. It is found that boron doping obviously enhances the growth rate of diamond films. A relatively high growth rate of 544 nm/h was obtained for the BDD film deposited on the tungsten carbide at 650 °C. The added boron-containing precursor gas apparently reduced activation energy of film growth to be 53.1 kJ/mol, thus accelerated the rate of deposition chemical reaction. Moreover, Raman and XRD analysis showed that heavy boron doping (750 and 850 °C) deteriorated the diamond crystallinity and produced a high defect density in the BDD films. Overall, 600–700 °C is found to be an optimum substrate temperature range for depositing BDD films on tungsten carbide substrate.     

Residual stress distribution in thin diamond films and its effects on preparation of thick freestanding diamond films using DC arc plasma jet operated at gas recycling mode

Diamond films produced by chemical vapor deposition show excellent properties. The residual stress distribution of diamond thin films deposited by DC arc plasma jet at recycling mode was analyzed by line shifts of micro Raman spectroscopy. The results show that the compressive residual stress concentrates at the film's edge. The experimental observations show that cracks initiate at the edge of the diamond thick wafer and then propagate towards the center. The residual stress of diamond films increases with the increase of methane concentration and deposition temperature. The difference of adhesion in close area causes more shear stress and brings about the two sides of crack being not at same level. To suppress crack probability, it is favourable for increasing the film thickness and selecting a substrate with lower coefficient of thermal expansion and lower adhesion. The effects of the residual stress distribution on thick diamond films detachment were discussed.     

金刚石膜抛光装置的有限元分析

本文建立了金刚石膜抛光装置的实体模型,采用接触分析法计算抛光装置高速旋转时,抛光盘厚度和转速对抛光装置的强度、刚度的影响规律。结果表明：随着金刚石膜抛光盘厚度的增加,同一转速下,vonMises等效应力与径向位移的变化很小,而轴向位移在抛光盘厚度较小时呈直线上升趋势,当抛光盘厚度大于等于8mm时,轴向位移的变化逐渐趋于平稳。同时,对于同一厚度的金刚石膜抛光装置,随着转速的提高,vonMises等效应力和径向位移呈现相似的上升趋势,轴向位移却先上升后下降。文中得出的结论为金刚石膜超高速抛光机的设计和实际操作,提供了可靠的理论依据。     

Interface diffusion of sputtered CoZrNb films on silicon substrate

The amorphous CoZrNb films were deposited by DC magnetron sputtering.The depth distributions of the elements were analyzed by Rutherford backscattering spectrometry (RBS).The results indicate that when the deposition time is longer than 37 min, the film composition keeps constant along the depth.When the deposition time is longer than 45 min, the Co concentration at the interface of the silicon substrate is higher than the average value in the whole film.When the deposition time is longer than 52 min, the Co atoms diffuse into the substrate during the deposition.According to the Co composition profile in the substrate, which were determined from the RBS spectra, the Co diffusion coefficients in the substrate were calculated using the solution of Fick's second law corresponding to an infinite source with a constant diffusion coefficient.The calculated diffusion coefficients indicate an interstitial assisted diffusion mechanism.     

硼掺杂对钛基金刚石薄膜附着力的影响

采用微波等离子体化学气相沉积(MPCVD)技术在钛基片上沉积了掺硼金刚石薄膜,并对掺杂前后的薄膜形貌及结构进行了检测.结果表明掺杂元素对形貌和结构有很大的影响,同时掺杂后薄膜与基底附着力有所下降.掠角衍射(GIXD)检测表明,中间层的主要成分是TiC和TiH_2.随着硼的加入,两者的含量增加.薄膜与基底的附着力下降的原因主要是受中间过渡层成分和残余应力增加的共同影响.