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。     

氩气与氮气流量比对磁控溅射法制备TiN薄膜的影响

用直流反应磁控溅射法在Si(100)基底上制备了TiN薄膜,采用X射线衍射仪和原子力显微镜对其结构和形貌进行了表征,利用四探针测试仪测量了TiN薄膜的方块电阻,使用紫外可见分光光度计测定了薄膜反射率;研究了溅射沉积过程中氩气与氮气流量比对TiN薄膜结构及性能的影响.结果表明:在不同氩气与氮气流量比下,所制备薄膜的主要组成相是(200)择优取向的立方相TiN;随着氩气与氮气流量比的增加,薄膜厚度逐渐增大,而表面粗糙度与电阻率先减小后增大;当氩气与氮气流量比为15:1时,薄膜表面粗糙度和电阻率均达到最小值;TiN薄膜的反射率与氩气与氮气流量比的关系不大.     

磁控溅射Ni56Mn27Ga17合金薄膜的光学反射特性研究

Ni-Mn-Ga磁性形状记忆合金薄膜是非常有用的多功能材料,为考察其光学反射特性,采用磁控溅射技术在单晶硅衬底上沉积了Ni56Mn27Ga17合金薄膜,并对其表面形貌和光学反射特性进行研究。研究结果表明,薄膜的表面粗糙度随退火温度的升高而增大;在300～800nm波长范围内,薄膜反射率均随波长的减小而降低,且薄膜整体谱线范围内的反射率随退火温度的升高而降低。     

锑掺杂纳米SnO2透明导电薄膜的制备与性能研究

采用溶胶-凝胶法在Si片、已镀SiO2的钠钙硅玻璃和普通钠钙硅玻璃上镀Sb掺杂摩尔分数为8%的SnO2薄膜(ATO),在450℃热处理温度下对薄膜结构,电学、光学性能进行表征。结果表明:薄膜以四方金红石结构存在,结晶完全;方阻值随镀膜层数的增加而明显降低,12层时薄膜最低方阻值为129Ω/□,可见光平均透过率在75%以上。随着波长的增大,红外波段的反射率逐渐增大,从15%增加到55%左右。     

Ag层厚度对AZO/Ag/AZO薄膜性能影响的研究

透明导电薄膜广泛应用于太阳能电池、触控面板、液晶显示等领域。本文采用磁控溅射法制备AZO/Ag/AZO透明导电薄膜，研究Ag层厚度对AZO/Ag/AZO透明导电薄膜光电性能的影响。结果表明，AZO薄膜是具有六方晶系ZnO纤锌矿结构的多晶相。当Ag层厚度增加时，AZO/Ag/AZO薄膜的（002）衍射峰略向较高的角度移动且半高宽略微增大，晶粒尺寸和晶面间距减小。AZO/Ag/AZO薄膜的电阻率，方块电阻，光学透射率与Ag层的厚度密切相关。随着Ag层厚度的增加，电阻率减小，透射率减小。品质因数表明，其中Ag层厚为5nm的AZO/Ag/AZO三层薄膜具有较好的光电性能。     

工件台偏压对非平衡磁控溅射沉积MoS_2-Ti薄膜的结构与性能影响

采用非平衡磁控溅射技术制备MoS2-Ti薄膜,研究工件台偏压对薄膜结构和性能的影响。利用XRF和XRD分析薄膜的成分和晶相结构,用CSM薄膜综合性能测试仪测试薄膜的厚度、硬度以及膜与基体的结合力,采用球-盘摩擦磨损试验机评价薄膜在真空环境下的摩擦学性能。结果表明:MoS2-Ti薄膜具有明显的(002)优势取向,薄膜中S、Mo原子比及膜厚随偏压的增加而减小,薄膜硬度及膜-基体附着力随偏压的增加而增大,薄膜在真空环境中的平均摩擦因数为0.02,受偏压影响不明显,薄膜寿命受偏压影响明显,当偏压在-100 V内变化时薄膜具有较长的寿命且随偏压的增加而增长,偏压继续增大薄膜耐磨寿命下降明显,当偏压为-200 V时薄膜不具备润滑性能。     

应力变化对多层薄膜窄带滤光片透射光谱的影响

利用薄膜应力公式和弹性力学的小挠度弯曲理论分析了在应力变化情况下,多层薄膜应变与膜厚变化的关系,并建立其数学模型,提出多层薄膜各层厚度变化的不均匀性理论.利用这个模型在应力减小200MPa条件下对138层4腔的100GHz滤光片光谱进行了模拟,与设计值比较发现中心波长增加了0.562nm;0.5dB处的带宽比设计值减小0.124nm;25dB处的带宽比设计值减小0.01nm;谱线矩形化变差;插损也有明显的增加.说明了应力变化引起的光学薄膜厚度变化的不均匀性是引起这种窄带干涉滤光片光谱退化的主要原因之一.实验结果为100GHz的窄带滤光片热处理后中心波长增加0.325nm;0.5dB处带宽减少0.01nm;20dB处带宽增加0.014nm;插损增加,谱线通带变形严重,纹波增大,光谱退化了.实验结果与理论分析一致.     

柔性衬底直流磁控溅射ZnO基高性能透明导电薄膜的制备及性能研究

采用直流磁控溅射法,以柔性PET(聚对苯二甲酸乙二醇酯)为基底,通过参数优化以求在室温下制备高性能ZnO/Ag/ZnO多层薄膜。实验中,使用X射线衍射仪(XRD)、原子力显微镜(AFM)、紫外-可见分光光度计、四探针电阻测试仪等仪器分别对ZnO/Ag/ZnO多层薄膜的微观结构、表面形貌、透过率及方块电阻进行测试及表征。结果表明,随着Ag层厚度增加,薄膜方块电阻急剧下降,通过改变ZnO层厚度,可有效调节薄膜光学性能,随着ZnO层厚度增加,可见光区平均透过率先增大后减小。引入品质因子FTC作为评价指标可知,当依次沉积ZnO、Ag、ZnO厚度为50nm、8nm、50nm时,薄膜光电性能最佳,其在可见光平均透过率为82.3%、方块电阻为2.8Ω/、禁带宽度为3.332eV。     

磁控溅射法制备的五氧化二钒薄膜光电特性

利用射频磁控溅射方法,选取溅射时间为15,25,30和45min,在蓝宝石衬底上沉积了V2O5薄膜。研究了其他实验参量不变,溅射时间不同对薄膜结构、薄膜厚度、表面形貌、电学及光学性能的影响。实验结果表明,制备出的薄膜为单一组分的V2O5薄膜,其在(001)面有明显的择优取向。随着溅身时间的增加,结晶性能逐渐变强,晶粒尺寸也逐渐变大,而表面粗糙度值会逐渐降低;在晶体结构完整的基础上,随着溅射时间的增加,相变温度和经历的温度范围会逐渐增加,电学突变性能会降低。测试了薄膜在中红外波段的高低温透过率,结果显示:当膜厚为350nm,波长为5μm时,薄膜的透过率从25℃时的81%变为300℃的7%,变化幅度可达74%;所有薄膜相变前后透过率的比值均为9~13,表现出了非常突出的光学开关特性。     

基于Au-Ag复合膜的光纤表面等离子体共振传感器理论仿真研究

为增强基于Ag膜光纤表面等离子体共振(SPR)传感器的抗氧化能力,可将Au膜镀于Ag膜表面。利用TFCalc软件对不同厚度Ag膜和Au-Ag复合膜的光纤SPR传感特性进行理论仿真研究。仿真结果表明:光纤SPR吸收峰显著依赖于Ag膜厚度,当Ag膜厚度由40nm逐渐增加到80nm时,共振吸收峰的半峰全宽逐渐减小,且共振波长随Ag膜厚度的增大而减小,共振波长变化范围较小,仅为7nm左右;Au膜的引入对共振吸收峰反射率影响不大,不同厚度Au-Ag复合膜的SPR共振波长随Au膜厚度的增大而增大。     

窄带Mo／Si多层膜反射镜

设计并制备了窄带M o/S i多层膜反射镜。利用高反射级次和减小M o层厚度两种方法减小M o/S i多层膜反射镜光谱宽度。对M o层厚度分别为2 nm和3 nm的M o/S i多层膜,设计了反射级次分别从1到6的多层膜系。制备方法采用直流磁控溅射技术,在国家同步辐射光谱与计量站上测试。结果表明,带宽随着反射级次增加而减少,在同一反射级次,M o层厚度为2 nm的多层膜反射光谱带宽较小。     

Reducing Friction Force of Si Material by Means of Atomic Layer-Deposited ZnO Films

With excellent lubricating property, zinc oxide (ZnO) films are promising candidates to act as protective coatings in Si-based microelectromechanical system devices for the purpose of decreasing friction forces of silicon (Si) material. In this paper, the nanotribological behavior of ZnO films prepared by atomic layer deposition on a Si (100) substrate is investigated by an atomic force microscope. The ZnO films have various thicknesses ranging from 10.0 to 182.1 nm. With the increase of film thickness, the root-mean-square roughness of the films increases, while the ratio of hardness to Young’s modulus (H/E) decreases. Due to their large surface roughness, the thick ZnO films are low in adhesion force. The friction force of the ZnO films is smaller than that of the Si (100) substrate and is greatly influenced by their adhesion force and mechanical property. In a low-load condition, the friction force is dominated by the adhesion force, and thus, the friction force of the ZnO films decreases as film thickness increases. While in a high-load condition, the friction force is dominated by plowing. Films with higher H/E possess smaller friction force, and thus, the friction force increases with the decreasing film thickness.     

Ni80Cr20合金薄膜制备影响因素的试验研究

利用直流磁控溅射的方法制备Ni80Cr20合金薄膜,以氩气流量、氩气工作压强、溅射功率作为三因素进行正交试验,在溅射时间相同的条件下分别测试了薄膜厚度、表面粗糙度、电阻率并进行了极差分析。分析结果表明:在一定范围内,氩气工作压强与溅射功率对薄膜厚度的影响较大;在氩气工作压强为3.0Pa时,薄膜厚度与溅射功率近似成正比关系;随着氩气流量的增大,Ni80Cr20薄膜厚度呈现先增大后减小的趋势;在氩气流量为50cm~3/min时,薄膜厚度达到最大值;各因素对薄膜表面粗糙度及电阻率影响不明显。     

Thin multilayer aluminum structures for superconducting devices

Various aluminum-based thin-film structures were manufactured and investigated at temperatures of 50 mK–3 K. Multilayer films of Al and Si, Al and Cr, and Al in the presence of oxygen were deposited by the thermal evaporation technique. As the thickness of pure-Al films decreases from 20 to 3 nm, the temperature of the superconducting transition increases from 1.30 to 2.45 K. An increase in the oxygen pressure to 5 × 10⁻⁶ mbar during deposition of Al films results in an increase in the critical temperature to 2.4 K. The presence of a chromium sublayer with a thickness of <0.5 nm may lead to complete suppression of superconductivity, whereas a thicker layer, 1–4 nm, deposited at a higher temperature with preliminary sputtering reduces the critical current of Al/Cr two-layer films to a lower degree. An atomic-force microscope was used to study the surface morphology and granularity and the roughness of manufactured film structures. The smallest linear roughness having a size of 0.29 nm for a 3-nm-thick film shows the advantage of using thinner films for creating a homogeneous tunneling barrier.     

Rhodium coated mirrors deposited by magnetron sputtering for fusion applications

Metallic mirrors will be essential components of all optical spectroscopy and imaging systems for ITER plasma diagnostics. Any change in the mirror performance, in particular, its reflectivity, due to erosion of the surface by charge exchange neutrals or deposition of impurities will influence the quality and reliability of the detected signals. Due to its high reflectivity in the visible wavelength range and its low sputtering yield, rhodium appears as an attractive material for first mirrors in ITER. However, the very high price of the raw material calls for using it in the form of a film deposited onto metallic substrates. The development of a reliable technique for the preparation of high reflectivity rhodium films is therefore of the highest importance. Rhodium layers with thicknesses of up to 2 microm were produced on different substrates of interest (Mo, stainless steel, Cu) by magnetron sputtering. Produced films exhibit a low roughness and crystallite size of about 10 nm with a dense columnar structure. No impurities were detected on the surface after deposition. Scratch tests demonstrate that adhesion properties increase with substrate hardness. Detailed optical characterizations of Rh-coated mirrors as well as results of erosion tests performed both under laboratory conditions and in the TEXTOR tokamak are presented in this paper.     

Density Variation in the Ultrathin Liquid Perfluoropolyether Films on Solid Surfaces

Variation of density in the ultrathin liquid perfluoropolyether films on solid surfaces has been studied by Monte Carlo simulations of Lennard-Jones systems. The liquid film is 8.75 nm thin film consisting of polymer molecules assuming the structure of perfluoropolyether Z having molecular weights of 3840, 2500 and 1700 g/mol and interacting among themselves by Lennard-Jones potential. The substrate is assumed to be continuous without atomic structure and exerting Lennard-Jones potential on liquid molecules in the ultrathin film. The system temperature is considered to be 25 °C and the liquid molecules also have the gravitational potential. It is found that the bead density decreases towards the surface in a thinner sublayer in the ultrathin liquid film above the surface and the thickness of this sublayer just above the surface may increase with the increase of molecular weight of the of polymers in the film. Repulsive potential of the surface further decreases the bead density near the surface. The results are compared with the experimental results of the pefluoropolyether lurbricants by X-ray reflectivity (Shouji, et al., 1998).     

基于离子束溅射Ta2O5薄膜的紫外吸收膜技术

为获得高性能紫外激光薄膜元件,急需研制紫外高反射吸收薄膜,实现吸收损耗的精确测量。本文采用离子束溅射技术,通过调控氧气流量实现了具有不同吸收的Ta_2O_5薄膜的制备。以Ta_2O_5薄膜作为高折射率材料,设计了355nm的紫外高反射吸收薄膜。采用离子束溅射沉积技术,在熔融石英基底上制备了355nm的吸收薄膜,对于A=5%的紫外吸收光谱,在355nm的透射率、反射率和吸收率分别为0.1%,95.0%和4.9%;对于A=12%的紫外吸收光谱,在355nm的透射率、反射率和吸收率分别为0.1%,87.4%和12.5%。实验结果表明,采用离子束溅射沉积技术,可以实现不同吸收率的355nm高反射吸收薄膜的制备,对于基于光热偏转测量技术的紫外光学薄膜弱吸收测量仪的定标具有重要的意义。     

真空热处理对硫化锌薄膜光学与微结构特性的影响

针对电子束蒸发离子辅助沉积的硫化锌薄膜,研究了550℃以下真空热处理对其光学与微结构特性的影响。薄膜光学和微结构特性的测试分析表明:制备后薄膜为类立方结构的ZnS,在337.5nm波长处出现临界特性转折点,随着热处理温度的增加,转折波长两侧的消光系数变化规律相反,折射率和物理厚度呈现下降趋势,薄膜的禁带宽度逐渐增加;在红外波段的薄膜折射率与热处理温度的变化并不显著,在350℃下热处理时消光系数出现转折,主要是由晶粒变小的趋势所致;通过晶相分析,硫化锌薄膜经历了类立方结构到六方结构的转换,与禁带宽度的变化趋势基本一致。分析结果表明,光学特性变化的根本原因是薄膜的微结构特性变化。