紫外激光单脉冲辐照损伤金属薄膜的数值模拟研究

针对不同厚度的镍膜以及金膜,利用多物理场耦合分析软件COMSOL Multiphysics研究了波长248nm、矩形脉冲宽度14ns激光辐照损伤阈值随膜厚变化的物理过程。本研究与他人的理论计算和实验测得的结果基本一致,研究表明:在高强度单脉冲激光均匀辐照下,金属薄膜表面的损伤主要是由于激光能量在其材料内部的沉积而导致的热效应引起的;当金属薄膜的厚度小于其光学吸收长度时(镍膜厚度<8nm,金膜厚度<12nm),其熔融损伤阈值随着薄膜厚度的增加而减小;当薄膜厚度大于光学吸收长度而小于其热扩散长度时(镍膜厚度8~730nm,金膜厚度12~1 050nm),其熔融损伤阈值随薄膜厚度增加而线性增加;当薄膜厚度大于其热扩散长度时(镍膜厚度>730nm,金膜厚度>1 050nm),其熔融损伤阈值随薄膜厚度的增大基本保持不变。     

铁电薄膜的制备方法

介绍了制备铁电薄膜的几种不同种类的方法.LSMCD技术是一种新型的制备铁电薄膜的技术.采用超声雾化产生微米级或亚微米级尺寸的气雾,再用载气将气雾引入沉积室内,沉积在基片上.重复此过程直至膜厚达到所需厚度.     

氮化硅陶瓷表面DLC膜的制备及摩擦性能研究

利用等离子体基离子注入与沉积技术,在氮化硅陶瓷片表面制备200～400nm的类金刚石碳膜。测试薄膜的厚度、表面形貌、结构、膜基结合力,利用球盘试验机考察DLC膜的摩擦性能。结果表明:沉积薄膜均匀光滑;薄膜的硬度和弹性模量与基体差异较小,膜基结合力强;DLC膜具有较低的摩擦因数,抗磨性能优异。     

纳米尺度金属薄膜在拉伸状态下的稳定性

将薄膜和基底作为一个基本结构来研究薄膜的变形和损坏可预测纳米薄膜器件的使用寿命.本文讨论和研究了薄膜基底结构在拉伸载荷下薄膜出现的分叉和断裂的过程.用在相同厚度的PET基底上沉积不同厚度铝膜的薄膜基底结构作为试件,分别对薄膜厚度为100,150和200 nm的3种不同试件进行了拉伸加载实验,并在OLYMPUS显微镜下观...     

掠出射微区X射线荧光分析系统的建立及其在薄膜分析中的应用

介绍了一种综合导管X光透镜及全反射X射线荧光分析技术的掠出射微区X射线荧光分析方法,并将其应用北京师范大学低能核物理研究所离子束物理与技术教研室采用MEVVA源离子束和薄膜沉积技术制备的纳米金属单层纳米薄膜及纳米多层膜的分析。实验中所用X光透镜的焦斑大小为41.7μm。通过对薄膜样品的掠出射角度扫描分析,可得到薄膜特征X射线的掠出射角分布曲线,通过将实验曲线与理论模拟曲线进行拟合,可得到薄膜样品在微小区域的厚度及密度。结果表明,相比于通过薄膜沉积过程中的离子电量估计的薄膜厚度值,该方法测出的薄膜厚度更接近于薄膜的实际厚度。同时结果表明,使用MEVVA离子束薄膜沉积技术所镀薄膜的密度均小于体材料样品的密度值,且薄膜厚度的增加,薄膜密度逐渐增大并接近于体材料的密度值。另外,通过对薄膜样品表面进行二维扫描分析,实验中,扫描步长为50μm,扫描区域为500μm*500μm,可分析薄膜表面微小区域的均匀性。     

TiN薄膜的残余应力调控及力学性能研究

残余应力是制约物理气相沉积（Physical vapor deposition,PVD）硬质薄膜厚度的关键因素。采用多弧离子镀技术在高速钢基体上制备了厚度从3.7 m到15.5 m的TiN薄膜,结合曲率法和有限元法研究残余应力及结合性能随膜厚的变化规律。结果表明,随着膜厚的增加,基片弯曲程度加剧,而薄膜平均残余应力降低;膜层内残余应力的整体水平决定了界面切应力大小,薄膜结合性能随界面切应力的增加而降低。增加基体偏压、降低工作气压均导致薄膜内部残余应力的升高。当残余压应力较高时,TiN薄膜具有细小、致密的柱状晶结构,并呈现（111）择优取向,薄膜硬度及断裂韧度较高,耐磨性能良好。研究结果提示我们,通过残余应力的调控可提高硬质薄膜的力学特性。     

摩擦偶件对PDDA/PSS分子沉积膜摩擦磨损行为的影响

利用分子沉积技术在单晶硅基底上制备了PDDA/PSS分子沉积膜。采用UV-vis吸收光谱对沉积过程进行了跟踪检测,用原子力显微镜观察了分子沉积膜的表面形貌,考察了摩擦偶件材料对PDDA/PSS分子沉积膜摩擦学行为的影响,并探讨了其磨损机制。实验结果表明,薄膜与较硬的偶件材料对摩时,剪切应力较大,薄膜很容易被磨穿,抗磨寿命极短;在相同实验条件下,薄膜与Cu球对摩时,薄膜的耐磨寿命最长,不锈钢球次之,与Si3N4球和WC球对摩时,薄膜的耐磨寿命较短。     

热丝CVD法制备大面积金刚石薄膜基片的变形

采用热丝CVD法制备的大面积金刚石薄膜存在基片变形严重的问题,通过对热丝CVD设备和沉积工艺进行改进,成功解决了直径76mm、厚度0.4mm硅片的变形问题。结果表明:改进后金刚石薄膜基片的翘曲度为0.296%,比改进前的降低了88.9%;改进后金刚石薄膜的质量及晶粒大小均匀,膜厚不均匀度仅为1.53%,具有优异的大面积均匀性。     

溅射法制备多层膜沉积速率的标定

为消除溅射沉积多层膜过程中产生的膜厚随机误差,实现多层膜膜厚的精确控制,提出了一种精确标定薄膜沉积速率的方法。该方法通过对多次实验结果进行最小二乘拟合得到薄膜沉积速率。对随机误差基本特性的分析表明,随着实验次数的增加,沉积速率将逐渐逼近真值。基于这一原理,可以对薄膜的沉积速率进行精确标定,同时提取出膜厚随机误差,进而确定镀膜机的膜厚控制精度,获得精确控制多层膜膜厚所需要的完整信息。选用两种精度不同的沉积设备,采用提出的方法对所制备的多层膜进行了测试。结果表明,多层膜的膜厚控制精度随沉积设备而异:其中低成本的普通镀膜机只能实现0.1 nm的膜厚控制精度;而另一台性能较高的镀膜机的膜厚控制精度优于0.01 nm。     

eXTP望远镜用W/Si多层膜

针对增强型X射线时变与偏振探测卫星(eXTP)项目中嵌套式聚焦成像望远镜对柱面镜片上W/Si多层膜的要求,在掠入射角为0.5°,工作波段为1~30keV条件下,设计了非周期W/Si多层膜并优化了薄膜制备工艺。首先,利用分隔板和掩模板对溅射粒子进行准直,同时优化了本底真空度和溅射工作气压,提升了薄膜的成膜质量;然后,通过调整分隔板间距和公转速率提升了在柱面基底上薄膜的沉积均匀性;最后,利用幂指数算法设计了非周期多层膜,并在北京同步辐射光源上进行了多能点反射率测试,得到了与理论设计基本吻合的测试结果。基于优化的制备工艺制备了周期数为80,周期为3.8nm和W膜层厚度占比为0.47的W/Si周期多层膜,其界面粗糙度仅为0.29nm,柱面镜薄膜厚度误差可控制在3%以内,基本满足了eXTP项目中嵌套式掠入射望远镜镜片用多层膜对于成膜质量、沉积厚度均匀性和能谱响应宽度的需求。     

铌酸锶钡铁电薄膜的微结构与薄膜厚度的关系

叙述了使用溶胶—凝胶法在 Si( 0 0 1 )基片上制备不同厚度的铁电铌酸锶钡薄膜的过程 ,使用 X射线衍射 ,扫描电子显微镜 ,拉曼散射光谱等方法研究薄膜的微结构与薄膜厚度之间的关系 ,薄膜的厚度一直能够达到 5 μm。实验发现 ,随着厚度的增加 ,SBN60薄膜在 ( 0 0 1 )方向的优先取向性越来越好。在逐层生长的过程中 ,处于底层的膜层能够起到缓冲层的作用 ,以逐渐改善薄膜与基片之间的晶格失配 ,从而使得晶体的结晶取向性越来越好     

Substrate surface energy effects on a liquid lubricant film at nanometre scalesubstrate surface energy effects on a liquid lubricant film at nanometre scale

In this paper is discussed the effect of the physical characteristics of substrate surfaces on the lubrication properties of thin films at nanometre scale. Different coatings with different surface energies have been formed on the surface of a steel ball by means of plasma assisted sedimentation (PAS). The ball was put in a pure rolling system in point contact, where the lubricant film is measured by relative optical interference intensity (ROII). Experimental results show that the film thickness is closely related to the substrate surface energy when the film is in the nanometre scale, and that the combined surface roughness in the contact region is closely related to the liquid lubricant film thickness and the contact pressure. The thinner the film and the higher the contact pressure, the smaller will be the combined surface roughness. Lastly, the relationship between critical film thickness and its influencing factors is discussed.     

Stress distribution of coated film with a range of coated film thickness and elastic properties under a single EHL operating condition

In recent years, the techniques improving sliding performances have progressed by using coated films possessing superior tribological properties, to reduce the failures of the mechanical elements. Those techniques are often used under severe conditions such as elastohydrodynamic lubrication (EHL). In this paper, numerical three-dimensional analysis of the maximum shear stress applied into the coated film and substrate under a single EHL operating condition was performed with a range of coated film thickness and elastic properties. The strength of coated film as one of those techniques was evaluated numerically, resulting in an optimum design of coated film. As a result, coated films with a larger value of thickness and a smaller modulus of elasticity than that of substrate are preferable.     

Tribological characteristics of gold films deposited on metals by ion plating and vapor deposition

Recent work on the graded interface between an ion-plated film and a substrate is discussed as well as the friction and wear properties of ionplated gold. X-ray photoelectron spectroscopy, depth profiling and microhardness measurements were used to investigate the interface. The friction and wear properties of ion-plated and vapor-deposited gold films were studied both in an ultrahigh vacuum system to maximize adhesion and in oil to minimize adhesion. The results of the investigation indicate that the solubility of gold in the substrate material controls the depth of the graded interface. Thermal and chemical diffusion mechanisms are thought to be involved in the formation of the Au-Ni interface. In the Fe-Au graded inter- face, gold was slightly dispersed in the iron and formed only a physically bonded interface. The hardness of the gold film was influenced by the thickness and was also related to the composition gradient between the gold and the substrate. A graded Ni-Au interface exhibited the highest hardness because of an alloy hardening effect. The effects of film thickness on adhesion and friction were established. A minimum coefficient of friction was found in the thin film region. No graded interfaces were detected in this investigation between vapor-deposited gold films and substrates.     

Study on the effect of DIC deformation sensor on mechanical property of substrate

The thin epoxy film with micro-scale speckle pattern as a digital image correlation (DIC) deformation sensor has been fabricated or transferred on the surface of sample in the previous study. When the thickness of the film cannot be ignored, it may have an influence on the validity of measurement results. And thus, the influence of the thin epoxy film on mechanical properties of substrates should be investigated. In this study, the mechanical behavior of thin film itself and surface strain of composite structure of thin film and substrate were measured using micro digital image correlation (MDIC) method. And theoretical and simulative results were also analyzed. From the comparison analysis of theoretical, simulative and experimental results, it is concluded that when the ratios of Young’s modulus and thickness between the film and substrate are smaller than 13 and 0.5 respectively, the influence from the thin film can be ignored, and thin epoxy film as DIC sensor can be used to measure the deformation of substrate.     

薄膜/基体结构的纳米压痕实验及其有限元分析

利用纳米压痕实验测定了氮化钛薄膜/高速钢基体中薄膜的弹性模量和硬度,并得到了纳米压痕过程的载荷—位移曲线;根据实验所得材料参数建立了纳米压痕实验的DEFORM计算模型,利用该有限元模型分析了不同薄膜厚度的膜/基结合处的切应力分布,研究了膜/基分离的可能性大小及分离位置与薄膜厚度的关系。     

覆膜铁熔融覆膜过程界面传热与熔膜填充行为研究

覆膜铁是金属包装领域的新型复合材料。成品覆膜铁的界面结合强度和水透性取决于覆膜过程中高聚物薄膜熔融层的厚度和流动铺展行为。但覆膜过程复杂而迅速，且受钢板表面微观形貌影响，熔融层膜厚及其流动铺展行为难以精细调控。针对此，基于分形理论表征与重构基板带钢表面微观形貌；基于广义Maxwell模型试验建立聚合物膜的黏弹性本构关系；建立了考虑基板带钢表面微观形貌的覆膜过程有限元仿真模型，并试验验证了模型的准确性。研究表明，熔融层膜厚主要受基板带钢初始预热温度影响，界面填充率则主要受覆膜辊压力影响。高聚物膜熔融层厚度和界面填充率随基板带钢粗糙度降低以及基板带钢和覆膜辊初始预热温度增加而增加，且辊压力增加也导致界面填充率增加。这些规律被定量化描述，为精细化调控熔融层膜厚及其流动铺展行为提供了理论依据。     

溅射气压和衬底温度对Si1-xGex薄膜结构和光吸收性能的影响

采用射频磁控溅射法沉积了Si1-xGex薄膜,研究了溅射气压、衬底温度对薄膜结构、厚度、表面形貌、表面成分及光吸收性能的影响。结果表明:薄膜均为微晶结构且相组成不随溅射气压和衬底温度的改变而改变;随着溅射气压升高,薄膜结晶性能降低,升高衬底温度使其结晶性能提高;随气压或温度的升高,薄膜厚度均先增大后减小,在1.0Pa或400℃达到最大值;随温度的升高,薄膜表面团簇现象消失并变得平整致密,气压为8.0Pa时,表面有孔洞和沟道;随气压升高,薄膜中锗含量降低,光吸收强度减小,光学带隙增大;衬底温度的变化对光学带隙影响不大。     

2m大口径RB-SiC反射镜的磁控溅射改性

为了消除RB-SiC反射镜直接抛光后表面存在的微观缺陷,降低抛光后表面的粗糙度,提高表面质量,针对大口径SiC的特性,选择Si作为改性材料,利用磁控溅射技术对2m量级RB-SiC基底进行了表面改性。在自主研发的Φ3.2m的磁控溅射镀膜机上进行基底镀膜,利用计算机控制光学成型法对SiC基底进行了抛光改性。实验结果表明,改性层厚度达到15μm;在直径2.04m范围内,膜层厚度均匀性优于±2.5%;表面粗糙度由直接抛光的5.64nm(RMS)降低到0.78nm。由此说明磁控溅射技术能够用于大口径RB-SiC基底的表面改性,并且改性后大口径RB-SiC的性能可以满足高质量光学系统的要求。     

Cross-Section preparation for tem of film-substrate combinations with a large difference in sputtering yields

The preparation of cross-section samples of thin films for TEM, may be difficult and tedious, especially if the difference in chemical or physical etching rates is large between the film and the substrate. In this paper, a method is presented whereby cross-sections can be prepared even if the film and the substrate have a large difference in sputtering yield. By utilizing the strong angular dependence of the sputtering yield and sputter at a low ion incidence angle with respect to the substrate surface of 7–12° and, furthermore, by avoiding sputtering parallel to the interface, samples with homogeneous thickness can be obtained. The technique is demonstrated on reactively sputtered titanium nitride coatings on high speed steel substrates. The difference in sputtering yields is about three for this film-substrate combination with the substrate being sputtered fastest.