一维AlN纳米结构制备进展

采用CVD、碳纳米管模板法等方法已经制成了纳米线、纳米管等多种结构;同时研制成功多种一维纳米结构的阵列。用CVD方法合成的AlN纳米线直径为几十纳米、纳米线长度可以达到几十微米;用碳纳米管模板法可以控制AlN纳米线的直径。同时,AlN纳米线也已经在场致发射的研究领域得到应用。综述了AlN一维纳米结构材料的制备方法,分析研究了AlN一维纳米结构的合成反应机理和材料特性。     

热CVD法制备的碳纳米管线阵列的场发射特性

采用半导体光刻技术在硅衬底上获得图形化掩膜,然后用热化学气相淀积(T-CVD)的方法制备了图形化的碳纳米管线阵列,用扫描电镜和拉曼光谱仪对碳纳米管进行了表征.研究了图形化碳纳米管线阵列的场发射特性,并与无图形化处理的碳纳米管薄膜样品的场发射特性进行了比较.当发射电流密度达到10 μA/cm2时,无图形化处理的碳纳米管薄膜、10 μm碳纳米管线阵列以及2 μm碳纳米管线阵列样品的开启电场分别为3 V/μm、2.1 V/μm和1.7 V/μm;而当电场强度达3.67 V/μm时,相应的电流密度分别为2.57 mA/cm2、4.65 mA/cm2和7.87 mA/cm2. 实验结果表明,图形化处理后的碳纳米管作为场发射体,其场发射特性得到了明显的改善.对改善的原因进行了分析和讨论.     

新型高抗粘紫外纳米压印光刻胶的工艺研究

为了减少紫外纳米压印技术脱模过程中的接触粘附力,开发了一种新型高流动、抗粘的紫外纳米压印光刻胶。光刻胶以BMA为聚合单体,添加特定配比的交联剂和光引发剂配置而成。紫外纳米压印实验在本课题组自主研发的IL-NP04型纳米压印机上完成。实验得到光刻胶掩膜膜厚为1.21μm,结构尺寸深246nm,周期937.5nm。实验结果表明,在没有对石英模板表面进行修饰的情况下,该光刻胶依然表现出高可靠性和高图形转移分辨率,有效减少了紫外纳米压印工艺中的模板抗粘修饰的工艺步骤。     

ICP在仿壁虎刚毛硅模版制作中的应用

简单介绍了ICP(inductively coupled plasma)中的两种刻蚀工艺,阐述了以MEMS加工技术制备柔性仿壁虎刚毛阵列的方法,即利用ICP设备,采用低温(CRYO)工艺,在硅片上制作仿壁虎刚毛硅模版,然后注入有机硅胶成型,经剥离后得到柔性仿壁虎刚毛阵列。实验结果表明,该方法具有工艺实现简便、硅模版可重复使用的优点。场发射扫描电子显微镜SEM照片显示了直径2μm、间距6μm和直径5μm、间距20μm的柔性仿壁虎刚毛阵列。     

图案化铜纳米线阵列的制备

采用紫外光刻法制得图案化的阳极氧化铝模板。在模板上蒸镀金膜后,采用电化学沉积法制备了铜纳米线,用扫描电子显微镜观察,研究了最佳电化学沉积时间。结果表明,铜纳米线阵列的图案与掩膜的图案完全一致,呈直径约5μm的圆形。铜纳米线的长度随沉积时间的增加而增长,沉积时间20min,即可制得长度约5μm的铜纳米线阵列结构。在此基础上可研制微器件。     

纳米阵列结构功能材料的制备、性质及应用

综述了用径迹蚀刻膜模板和多孔阳极氧化铝模板等制备纳米阵列结构功能材料的方法,介绍了金属、半导体纳米阵列结构功能材料、碳纳米管阵列结构功能材料及纳米阵列复合材料的性质和应用实例,并探讨了其应用前景。     

100%填充因子的硅微透镜阵列的制作

本文成功制作出了表面光滑且具有100%填充因子的硅微阵列阵列结构。制作流程包括：旋涂光刻胶,热熔融和反应离子可是转移。首先,在硅衬底上旋涂SU-8光刻胶,并光刻显影;其次,热熔融和热处理光刻胶阵列得到光刻胶微透镜阵列;最后,反应离子刻蚀转移形成硅微透镜阵列。实验表明,通过调节反应离子刻蚀气体SF6和O2的量分别到60sccm和50sccm,就可以得到无间距的硅微透镜阵列。在此种情况下,光刻胶和硅衬底的刻蚀速率比值为1:1.44。单个微透镜底端尺寸为30.1微米,高度为3微米,焦距在15.4微米到16.6微米之间。     

背照式ZnO紫外焦平面成像阵列制作的刻蚀研究

研究了背照式ZnO焦平面成像阵列制作的刻蚀工艺.该ZnO焦平面阵列为128×128阵列,每个单元面积为25μm × 25μm,对该阵列的刻蚀结果进行了研究分析.刻蚀后阵列单元的剖面角约为80°.在刻蚀过程中,刻蚀深度和刻蚀时间呈线性关系.还研究了NH4Cl溶液浓度和刻蚀速率之间的关系.时刻蚀后的阵列单元进行了光电响应的测试,得到明暗电流比约为60:1.     

直流电沉积制备一维ZnSe半导体纳米材料

用二次阳极氧化法制备了多孔阳极氧化铝(AAO)模板。以AAO为模板,在ZnSO4、Na2SO4和H2SeO3的混合水溶液中进行直流电沉积了ZnSe半导体纳米线。SPM、TEM测试表明,模板表面形成模孔大小一致、排列规则的阵列。ZnSe纳米线的直径约为60nm,长度约为0.5μm并与模板的孔径和深度一致。在制备过程中,无需去除AAO的基底,喷金或预镀金属等处理,直接在AAO纳米孔内电沉积,制备纳米线。该方法简单、有效并且容易获得有序的半导体纳米线阵列。     

皮秒激光制备大面积荷叶结构及其硅橡胶超疏水性压印研究

超疏水自清洁荷叶结构表面有重要应用潜力。运用高功率皮秒激光结合高速扫描振镜,在H13模具钢表面高效制备了密排六方点阵微米级凹坑,其中含有丰富的纳米级亚结构,获得了面积为25mm×25mm的反荷叶结构。将该结构用于超疏水微纳米压印模板,在165℃、6MPa、大气环境中进行硅橡胶压印,获得大面积微米级突起阵列,表面分布着纳米级亚结构,与荷叶结构十分相似。压印后硅橡胶表面接触角达到153.3°,接触角滞后值为3.2°,实现了超疏水性。皮秒激光制备的模板能进行连续压印,具有一定的耐久性和连续压印能力。     

Microcontact printing of biomolecular gratings from SU-8 masters duplicated by Thermal Soft UV NIL

Thermal Soft UV nanoimprint lithography (NIL) was performed to replicate nanostructures in SU-8 resist. The SU-8 resist was structured with a PDMS stamp molded against an original silicon master which comported gratings of lines (500 nm width/1 μm pitch). The patterns obtained in SU-8 were used in a second step as a template for PDMS molding of daughter stamps. Pattern transfer quality and dimension control were achieved on these second generation PDMS stamps using AFM measurements. As a final validation of the whole duplication processes, these second generation PDMS stamps were finally employed to perform μCP of streptavidin molecules on a glass slide activated by plasma O₂ treatment. AFM observation and fluorescence microscopy reveal that molecular patterns produced with SU8-molded PDMS stamps are not discernable from those obtained with a PDMS stamp directly molded on the original silicon master. Coupling Thermal Soft UV NIL and microcontact printing opens a new method for generating a large quantity of SU-8 templates on which functional PDMS stamps can be replicated in a reduced time. We thus propose a functional duplication process for soft-lithography implementation which may further reduce the cost of this technology for industrial development.     

Fabrication of microstructures with high aspect ratios and great structural heights by synchrotron radiation lithography,galvanoforming, and plastic moulding (LIGA process)

Under the LIGA process for fabricating microstructures having high aspect ratios and great structural heights, synchrotron radiation lithography produces a primary template which is filled with a metal by electrodeposition. The metallic structure so produced is used as a mould insert for fabricating secondary plastic templates which, in mass production, replace the primary template. This is a report about the status of work performed by the Karlsruhe Nuclear Research Center with the cooperation of Siemens AG and the Fraunhofer Institute for Solid State Technology: By irradiation and development of polymethyl methacrylate (PMMA) plates, primary templates were produced which, for structural heights of several hundred μm, exhibit deviations in critical dimensions of less then some 0.1 μm. The best results were obtained with an X-ray mask consisting of a 25 μm thick beryllium foil and 18 μm thick absorber structures consisting of copper and gold. Practically perfect metallic replicas were obtained by electrodeposition of nickel in the PMMA microstructures and even details in structure of less than 0.1 μm size were reproduced. Moulding was done with a methacrylate-based casting resin with an internal mould release agent. By electrodeposition of nickel in the secondary templates, secondary metal structures were produced which practically do not differ from the primary structures. The LIGA process can be expected to be superior to other methods for fabricating microstructures with high aspect ratios if, in series production of microstructures with complex shapes, stringent requirements are imposed on the resolution, the aspect ratio, the structural height, and the parallelism of the structural walls.     

Spatial and Orientational Templating of Semiconducting Polymers in a Cholesteric Liquid Crystal

A one‐dimensional pattern‐forming state of a cholesteric liquid crystal (CLC) is used as a template for the self‐organization of ordered, spatially orientated, acetylene‐based semiconducting polymers. The polymers are formed by metathesis reaction with all chemical components contained in an ordinary electro‐optic cell. The polymer morphology consists of parallel ～ 1 μm thick bundles, uniformly spaced at ～ 10 μm over the full macroscopic active area of the cell substrates. The polymer templating can be explained by a model that predicts a corrugation in polymer density determined by the spatially periodic profile of the orientational energy density associated with the pattern‐forming CLC state.     

Silica Films with Bimodal Pore Structure Prepared by Using Membranes as Templates and Amphiphiles as Porogens

Extended porous silica films with thicknesses in the range of 60 to 130 μm and pores on both the meso‐ and macroscale have been prepared by simultaneously using porous membrane templates and amphiphilic supramolecular aggregates as porogens. The macropore size is determined by the cellulose acetate or polyamide membrane structure and the mesopores by the chosen ethylene‐oxide‐based molecular self‐assembly (block copolymer or non‐ionic surfactants). Both the template and the porogen are removed during an annealing step leaving the amorphous silica material with a porous structure that results from sol–gel chemistry occurring in the aqueous domains of the amphiphilic liquid‐crystalline phases and casting of the initial template membrane. The surface area and total pore volume of the inorganic films vary from 473 to 856 m² g^–1, and 0.50 to 0.73 cm³ g^–1, respectively, depending on the choice of template and porogen. The combined benefits of both macro‐ and mesopores can potentially be obtained in one film. Such materials are envisaged to have applications in areas of large molecule (biomolecule) separation and catalysis. Enhanced gas and liquid flow rates through such membranes, due to the presence of the larger pores, also makes them attractive as supports for other catalytic materials.     

Content-addressable memory for VLSI pattern inspection

In the template-set approach to VLSI pattern inspection, all patterns in a local window (i.e. a 5×5 array of pixels) that are allowed by the design rules are collected as a template set, and an image in the window centered at each pixel position is compared to the templates to determine whether the pattern is defective. To make this method practical, the number of acceptable templates must be reasonably small and template matching must be fast. By introducing don't-care conditions into the templates, the number of required templates was reduced. A maskable content-addressable memory was used to implement templates with don't-care conditions and to permit parallel comparison of an incoming pattern with all templates in the set. A custom VLSI chip was designed with a 2-μm double-metal CMOS technology, which can perform parallel template matching at the rate of 1.6×10⁷ local images per second     

Synthesis of Nanowalled Polymer Microtubes Using Glass Fiber Templates

Covalently crosslinked flexible polymer microtubes with wall thicknesses of 1–3 nm, diameters of 2–10 μm, and lengths of 0.1–0.5 mm have been fabricated using glass wool and silica wool as templates. Fluorescent‐dye‐tagged polyamines were adsorbed onto the glass and silica templates and crosslinked by reductive amination with glutaraldehyde and sodium cyanoborohydride, then the templates were dissolved with hydrofluoric acid. Microtubes were prepared from polyallylamine (PAA), polyethyleneimine (PEI), and poly(iminohexamethylene) (PIH) labeled with sulforhodamine B. These flexible hollow structures were characterized by bright‐field and fluorescent optical microscopy and confocal laser scanning microscopy; they adopt open tubular conformations when suspended in water, and dry to give flat ribbons.     

图像配准在TDICCD拼接焦面精度检测中的应用

大视场遥感相机需要进行TDICCD拼接,对拼接焦面的精度要求非常苛刻,必须进行精确的精度检测以确保良好的成像质量。检测拼接焦面精度时,选取TDICCD封装中几何结构简单明显的标志图形作为模板,采用图像配准的方法进行标志图形定位,提出了最优步进两步模板匹配算法实现图像配准,得到各片TDICCD的拼接误差数据,所有配准过程耗时不超过350 ms。图像配准方法采用统一的客观模板检测多片小像元TDICCD的拼接焦面,检测结果表明该方法可将每一片TDICCD像元的位置定位精度提高30.6%。图像配准拼接精度检测避免了常规检测方法通过人眼观测读取数据所引入的主观误差,取得的检测结果更为精确,同时精度检测过程不需要人工干预,提高了拼接精度检测工作的效率。     

Capillary Force Lithography: Fabrication of Functional Polymer Templates as Versatile Tools for Nanolithography

The implementation of high‐resolution polymer templates fabricated by capillary force lithography (CFL) is explored both in nanoimprint lithography (NIL) and in the wet‐etching of metals. Several different thermoplastic and UV‐curable polymers and types of substrates are incorporated into the general CFL procedure to meet the diverging requirements of these two applications. The mechanical stability of UV‐curable templates for imprinting in polymers, as examined by atomic force microscopy (AFM), and their anti‐adhesive properties are excellent for application in NIL. The conditions for curing the UV‐curable polymer are optimized in order to obtain high‐stability polymer templates. Gold patterns on silicon with a lateral resolution of 150 nm are fabricated by subsequent lift‐off in acetone. Similar patterns with a lateral resolution of 100 nm are fabricated using templates of thermoplastic polymers on gold layers on silicon as an etch mask. The transfer of stamp residues during CFL with these polymer templates is proven by X‐ray photoelectron spectroscopy (XPS) and AFM friction analysis. For poly(methylmethacrylate) (PMMA), the presence of large amounts of silicon‐containing residues is found to compromise the processability of the resulting template in subsequent O₂ reactive‐ion etching (RIE) treatment. The extent of silicon contamination is up to six times less for polystyrene (PS). At this level, the etch performance of the PS etch mask is not affected, as was the case for PMMA. Accurate downscaling of the lateral dimensions of the resulting metal patterns by several factors with respect to the dimensions of the PS etch mask is achieved by over‐etching of the gold. Overall, the results in this paper demonstrate the potential of CFL templates as tools for high‐resolution soft lithography.     

Fabrication of quasi-one dimension silicon carbide nanorods prepared by RF sputtering

Anodic aluminum oxide (AAO) template was prepared by a two-step anodization method at low temperature (1 °C) and silicon carbide was deposited on the templates by non-reactive radio frequency sputtering method. Well-aligned quasi-one dimension silicon carbide nanorods with the average diameter about 80-90 nm and a mean length of 400 nm were obtained perpendicular to the substrate and observed by AFM and SEM after the aluminum substrates were striped off. Then some samples were annealing at flowing N₂ at 400, 500 and 600 °C and FTIR was performed on these samples to obtain the information of structure.