溅射制作埋嵌电阻的TaN薄膜电阻率的控制

文章介绍的是由射频（RF）溅射反应沉淀制备的TaN薄膜,以及在各种N2/Ar气流比例和工作压力下测试其电阻率变化。从X射线衍射（X-RD）图像和四点探针测试仪测试的TaNx薄膜方块电阻来看。研究发现,TaNx薄膜电阻率发生突变的原因主要是由于N2分压的作用而使TaNx薄膜晶体结构发生了变化。当六边形结构的TaN薄膜变成面心立方行结构时,薄膜电阻从16Ω/sq增加到1396Ω/sq。但是,在晶体结构不变和一定的工作压力范围内,我们能把TaN薄膜的电阻率控制在69Ω/sq到875Ω/sq范围内。在扫描电子显微镜（SEM）成像中,晶粒尺寸随着工作压力的增加将会有所减小。     

玻璃纤维增强SU-8胶技术

SU-8胶是一种能够以低成本制作高深宽比微结构的负性光刻胶,在非硅微电子机械系统(MEMS)领域具有广阔的应用前景。针对SU-8胶作为微结构材料时,其弹性模量和断裂强度较低的特性,采用透明度高的微细玻璃纤维作为增强相材料,制备玻璃纤维/SU-8复合材料。开发出一种既能够增强成型后SU-8微结构机械强度,又不影响SU-8可直接光刻成型能力的改性技术。通过光学显微镜和扫描电子显微镜(SEM)对该复合材料的微观结构进行了分析和表征。同时,利用拉伸实验对复合材料的机械性能进行测试。实验结果表明,在不改变紫外光刻电铸(UV-LIGA)的光刻-显影工艺特征的条件下该复合材料的弹性模量(1 613 MPa)、断裂伸长率(1.63%)和断裂强度(26.7 MPa)均比纯SU-8胶材料有较大提升。     

一种近方脊滤波器的设计与快速制造

滤波器是信号传输系统中的重要组件。本文提出一中快速、高精度复制工艺方法,用于设计和制备WR-10波段矩形波导滤波器。采用多层匀胶单次紫外曝光工艺（硅片上匀SU-8胶）,制备出的滤波器高度误差小于0.03%（3um）,陡直度误差小于1.1o。实验结果表明,用该方法制备毫米波滤波器技术可行,并取得了卓越的电磁性能（关于：插入损耗,回波损耗和带宽）。最终测试结构可知,通带内的插入损耗测得结果小于0.5dB,几乎可以忽略不计,在整个通带内回拨损耗大于10 dB。结果表明,这种快速制造技术是制备太赫兹射频器件的一种有效办法,这种新技术将成为推动太赫兹射频器件未来发展的主要动力。     

镍/碳纳米管复合薄膜的制备及其性能的研究

结合电泳沉积碳纳米管和电镀金属镍的方法,在导电基片上成功制备了镍/碳纳米管复合薄膜.观察了薄膜的形貌和成份,测试了所制备的镍/碳纳米管复合薄膜的表面电阻和场发射特性,并与传统的电泳方法制备的碳纳米管薄膜进行了比较.实验结果表明,镍/碳纳米管复合薄膜表面碳纳米管大范围排布有序、密度可控;与传统电泳方法制备得到的碳纳米管薄膜相比,镍-碳纳米管复合薄膜具有更小的表面电阻和更好的场发射性能.镍层在薄膜中起到了固定碳纳米管、改善碳纳米管与基底以及碳纳米管与碳纳米管之间电接触的作用;由于镍在薄膜中含量较少(小于10%),薄膜整体仍体现出碳纳米管的优异性能.     

电阻法测试超薄膜厚度的研究

常规方法测试超薄膜的厚度存在很大困难。介绍一种测试约4nm PtSi厚度的电阻率法。先制备厚度约40nm的薄膜,测试出薄膜电阻率,再考虑超薄膜的表面效应、尺寸效应,推导出超薄膜电阻率与薄膜电阻率的关系式,测试超薄膜方电阻,计算出超薄膜厚度。给出了TEM晶格像验证结果,误差小于6%。实验表明该方法简单易行,对其他超薄膜厚度的测试提供了参考。     

一种近方脊滤波器的设计与快速制造（英文）

滤波器是信号传输系统中的重要组件.提出一种快速、高精度复制工艺方法,用于设计和制备WR-10波段矩形波导滤波器.采用多层匀胶单次紫外曝光工艺(硅片上匀SU-8胶),制备出的滤波器高度误差小于0.03%(3μm),陡直度误差小于1.1o.实验结果表明,用该方法制备毫米波滤波器技术可行,并取得了卓越的电磁性能(关于:插入损耗,回波损耗和带宽).最终测试结构可知,通带内的插入损耗测得结果小于0.5 dB,几乎可以忽略不计,在整个通带内回拨损耗大于10 dB.结果表明,这种快速制造技术是制备太赫兹射频器件的一种有效办法,这种新技术将成为推动太赫兹射频器件未来发展的主要动力.     

Sb掺杂对SnO_2薄膜光电性能的影响研究

以乙醇为溶剂采用溶胶-凝胶法制备出了Sb掺杂的SnO_2复合透明导电薄膜,并利用XRD,SEM,紫外-可见分光光度计,四探针电阻仪等测试方法对Sb掺杂的SnO_2复合薄膜的结构和物性进行了研究。结果表明,当Sb掺杂量小于摩尔分数7%时,SnO_2复合薄膜均呈四方金红石型晶体结构;随着Sb掺杂量的增加,薄膜电阻率先降低后增大,当Sb掺杂量为摩尔分数5%时,薄膜电阻率达到最小值1.4×10~(–3)?·cm。在350~700 nm波长范围内,当Sb掺杂量小于摩尔分数7%时,SnO_2复合薄膜的透过率均在80%以上。     

纳米银线-环氧树脂复合导电薄膜的制备及其在柔性触控上的应用

纳米银线透明导电薄膜具有优异的光电性能和机械性能,有望取代传统的氧化铟锡材料应用于柔性光电器件中。为解决纳米银线的黏附性、柔韧性和稳定性问题,结合转印法和烷基硫醇修饰法制备了纳米银线-环氧树脂复合导电薄膜。在此过程中,首先应用十八烷基三氯硅烷对转移衬底进行疏水化处理以提升透明电极转印的良率;接着,对转印后的纳米银线进行烷基硫醇分子的自组装修饰,以进一步提升纳米银线透明导电薄膜的稳定性;最后在此基础上制备了柔性投射式电容触控屏。所制备的透明导电薄膜具有优异的综合性能:品质因数约为300(Rs=29.7Ω/□,T=96.2%);薄膜经过100次胶带测试后,电阻变化小于25%;在1 000次弯曲(弯曲半径为1mm)测试后,电阻几乎不发生变化;高温高湿下老化一个月,电阻变化小于20%。本文结合转印工艺以及分子修饰技术开发的纳米银线-环氧树脂复合导电薄膜以及柔性触控工艺,有望推广应用至其他柔性电子元件中。     

用于红外探测的掺硼非晶硅薄膜电阻的热电特性研究

详细研究了等离子增强型化学气相沉积（PECVD）制作的掺硼非晶硅薄膜电阻的电阻率随各种制备条件的变化特性和它的热电特性,制作出了高灵敏度的适于作室温红外探测器敏感元件的掺硼a—Si薄膜电阻。制作的非晶硅电阻室温300K下的电阻温度系数（TCR）高达2．56％／℃,且制作工艺简单,与常规工艺兼容性好。     

磁控溅射氧化钛薄膜的电学特性研究

采用直流磁控溅射法在K9玻璃上制备了不同溅射温度和氧气流量的氧化钛(TiOx)薄膜.采用XPS、霍尔效应测试仪对薄膜的组份、载流子浓度和迁移率进行了测试,发现随着溅射氧气流量的增大,薄膜中的氧元素比例增大,载流子浓度减小,迁移率增大.分析了TiOx薄膜的电阻温度系数(TCR)与溅射温度和氧分压的关系,薄膜的电阻率从0....     

Effect of Carbon Nanotubes on the Shear Strength and Electrical Resistivity of a Lead-Free Solder

In this study, the influence of carbon nanotubes (CNTs) on the shear strength and electrical resistivity of 95.8Sn-3.5Ag-0.7Cu lead-free solder was investigated. Composite solders containing various weight percentages of CNTs were synthesized, and electrical resistivity results of the bulk composite solders revealed that the presence of CNTs did not degrade the electrical performance of such solders. Tests conducted on lap-shear solder joint samples showed an improvement in the shear strength of the composite solders. However, at higher amounts of CNT additions (0.04 wt.% and 0.07 wt.%), the strength improvement was only marginal compared to that of the monolithic solder joint. A comparison of yield stress and ultimate stress test results between the solder joint and bulk solder also showed good agreement. Furthermore, the presence of CNTs in the solder matrix had a minimal influence on the thickness of the interfacial intermetallic compound layer formed during soldering.     

Suspension of nanoparticles in SU-8: Processing and characterization of nanocomposite polymers

Composite materials consisting of polymers and nanoparticles can provide additional functionality to existing formulations. Diamondoids, single-wall carbon nanotubes (SWNT), and gold nanospheres were physically incorporated into the negative photoresist SU-8 to investigate their effects on residual stresses and introduce piezoresistivity. The mixtures were spin cast onto silicon or aluminum-coated silicon wafers, lithographically patterned and released from the substrate. The residual stresses, elastic moduli, and viscosity effects of the nanocomposites were measured and compared with those of control samples of SU-8. Electrical properties of SU-8/SWNT nanocomposites were also investigated. The effective elastic modulus of SU-8/diamantane samples remained approximately 1.5-1.6 GPa until the diamantane content exceeded 7 wt%. The viscosity of SU-8/diamantane nanocomposite samples of all tested weight percents decreased compared with control SU-8 at high shear rates (>20 Hz), though high weight percent solutions (>5%) had increased low-frequency viscosity. The effective elastic modulus of the SU-8/SWNT nanocomposites decreased with small wt% additions of SWNT. Additionally, SU-8/SWNT nanocomposites showed increased resistivity with increased strain, suggesting a gauge factor for the 1 wt% SU-8/SWNT nanocomposite of approximately 2-4.     

基于激光作用的含CNTs复合涂层的摩擦磨损研究

碳纳米管具有超强的力学性能,极高的纵横比、高的化学和热稳定性及导电性,是制备复合材料的理想组元。本文采用大功率CO2激光器,以45碳钢为基体,制备了激光熔覆的CNTs复合涂层。研究了在激光作用下,工艺参数对涂层性能的影响,并对复合涂层进行了摩擦磨损试验。试验结果表明:经激光熔覆处理制备的CNTs复合涂层,其耐磨性能显著提高,磨损失重是未处理的38%,摩擦系数也显著下降,是未处理试样的37%。     

High Electromechanical Response of Ionic Polymer Actuators with Controlled‐Morphology Aligned Carbon Nanotube/Nafion Nanocomposite Electrodes

Recent advances in fabricating controlled‐morphology vertically aligned carbon nanotubes (VA‐CNTs) with ultrahigh volume fraction create unique opportunities for markedly improving the electromechanical performance of ionic polymer conductor network composite (IPCNC) actuators. Continuous paths through inter‐VA‐CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast device actuation speed (>10% strain/second). One critical issue in developing advanced actuator materials is how to suppress the strain that does not contribute to the actuation (unwanted strain) thereby reducing actuation efficiency. Here, experiments demonstrate that the VA‐CNTs give an anisotropic elastic response in the composite electrodes, which suppresses the unwanted strain and markedly enhances the actuation strain (>8% strain under 4 V). The results reported here suggest pathways for optimizing the electrode morphology in IPCNCs using ultrahigh volume fraction VA‐CNTs to further enhanced performance.     

Carbon Nanotubes: High Electromechanical Response of Ionic Polymer Actuators with Controlled‐Morphology Aligned Carbon Nanotube/Nafion Nanocomposite Electrodes (Adv. Funct. Mater. 19/2010)

Recent advances in fabricating controlled‐morphology vertically aligned carbon nanotubes (VA‐CNTs) with ultrahigh volume fraction create unique opportunities for markedly improving the electromechanical performance of ionic polymer conductor network composite (IPCNC) actuators. Continuous paths through inter‐VA‐CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast device actuation speed (>10% strain/second). One critical issue in developing advanced actuator materials is how to suppress the strain that does not contribute to the actuation (unwanted strain) thereby reducing actuation efficiency. Here, experiments demonstrate that the VA‐CNTs give an anisotropic elastic response in the composite electrodes, which suppresses the unwanted strain and markedly enhances the actuation strain (>8% strain under 4 V). The results reported here suggest pathways for optimizing the electrode morphology in IPCNCs using ultrahigh volume fraction VA‐CNTs to further enhanced performance.     

CNTs-TiO2复合薄膜的场发射及其在电离规中的应用

介绍一种制备碳纳米管（CNTs）薄膜的方法—擦涂法。利用这种方法制备了CNTs薄膜以及CNTs-TiO2复合薄膜,对其场发射性能进行了研究,发现CNTs＋（7%～10%（质量比））TiO2复合薄膜的场发射性能与纯CNTs薄膜相比有较大改善,开启电场由2.5V/μm降低到1.3V/μm,阈值电场由4V/μm降低到3.1V/μm,场发射的均匀性与稳定性也有显著的提高。利用CNTs＋7%TiO2薄膜样品作为电离真空规的冷阴极,实现了在2×10-2～3×10-5 Pa范围内的近似线性响应,灵敏度约为3.36Pa-1。这种电离真空规具有体积小、低能耗的特点。     

Electrical Conductivity of Film Composites Based on Polyvinyledene Fluoride with Carbon Nanotubes

The results of a study of film composites based on polyvinylidene fluoride with carbon nanotubes (CNTs) by dielectric relaxation spectroscopy are presented. For composite samples containing more than 0.5 wt % of nanotubes, nonlinear current–voltage characteristics are obtained. The concentration dependences of the electrical conductivity of the composites are examined and the percolation threshold for the samples under study is determined. It is shown that an insignificant increase in the electrical conductivity of the composites is observed even upon filling with 0.2 wt % of CNTs, whereas the electrical conductivity becomes three orders of magnitude higher upon the introduction of 1 wt% of CNTs and is seven orders of magnitude higher at more than 3 wt %, compared with the unfilled polymer. This confirms that CNTs are promising for the development of electrically conducting composites and film materials on the basis of polyvinylidene fluoride.     

Carbon nanotubes and silver flakes filled epoxy resin for new hybrid conductive adhesives

Combining conductive micro and nanofillers is a new way to improve electrical conductivity. Micrometric silver flakes and nanometric carbon nanotubes (CNTs) exhibit high electrical conductivity. A new type of hybrid conductive adhesives filled with silver flakes and carbon nanotubes (DWCNTs or MWCNTs) were investigated. High electrical conductivity is measured as well as improved mechanical properties at room temperature. Small agglomerates and free MWCNTs dispersed in the silver/epoxy composites improve the electrical conductivity and a synergistic effect between MWCNTs and micro sized silver flakes is observed in hybrid composites. Glassy and rubbery storage moduli of the hybrid composites increase with increasing silver loading at fixed CNTs volume fraction. High value of the storage modulus, measured in DWCNTs/μAg hybrid composites at rubbery state, is caused by strong agglomeration of DWCNTs bundles. The electrical and mechanical properties are consistent with the morphologies of the hybrid composites characterized by SEM.     

微悬臂梁传感系统在CNT微热量检测中的应用

针对碳纳米管(CNT)微热量检测不易的问题,采用了一种基于微悬臂梁传感器的CNT微热量检测系统进行检测.通过光杠杆检测法测量微悬臂梁弯曲量,从而实现微悬臂梁对CNT的微热量检测,研究了CNT光热转换散发热量对微悬臂梁挠度的影响.用最小二乘法拟合出CNT薄膜温度变化与相应微悬臂梁偏移量关系.结果 显示,温度变化与微悬臂梁...     

Low-Resistance Carbon Nanotube Contact Plug to Silicon

We demonstrated the integration of carbon nanotubes (CNTs) as the contact plug to the Si MOSFET. A Ti silicide contact layer was introduced between the CNTs and the Si. The open-ended CNT tip connected the metal one on the other end. We study the contact resistivity of the CNT contact plug using the cross-bridge Kelvin test structure, and compare with the W contact plug. The CNT contact plug also showed excellent thermal stability. The electrical and thermal behavior is closely related to the intermediate layer between the CNT and the Si.