Name: atomically traceable nanostructure fabrication
Uploaded: 2015-07-17T15:00:00.000+00:00
Duration: 12 min 35 s
Description: Watch this Scientific Journal Video about Atomically Traceable Nanostructure Fabrication at JoVE.com

这项工作是由DARPA从（N66001-08-C-2040）合同，由得克萨斯州的新兴科技基金资助项目。作者要感谢智英金，格雷格Mordi，安吉拉Azcatl，汤姆沙尔夫对有关选择性原子层沉积的贡献，以及马丁·华莱士和戈登·波洛克易地来样加工。

1. 前原位样品制备<ol><li>芯片的准备<ol><li>设计适当的蚀刻掩模将确定在硅（100）晶圆标记。使用标准的光刻和RIE，蚀刻线作为基准标记成从该STM样品将要采取的晶片的一个网格。该线应为10微米宽，1微米深，并在500微米的间距。蚀刻后，剥去样本剩余的光刻胶。 注意:基准标记必须是可识别的原位上的样品，以及在AFM及SEM计量期间尖端位置。 </li><li>通过采用标准的粘性蓝色切割带，胶粘面朝下保护晶圆表面。 </li><li>骰子晶片成使用金刚石片放倒陶瓷切割锯成适合特定UHV-STM工具尺寸正用于执行高密度脂蛋白。这里，将样品分别为8.1毫米×8.1毫米正方形。 </li></ol></li><li>切割后，准备芯片插入UHV-STM图案化模具轻轻剥开切割带，注意不要接触芯片与任何含镍的工具，这将导致特高压准备下文第2节之后的不利表面重建。 <ol><li>清洁芯片通过漂洗正面每10秒用丙酮，异丙醇，甲醇和去离子水分别流，而夹持样品的侧面与聚四氟乙烯（PTFE）镊子。最后，用干超纯N 2或Ar，仍与聚四氟乙烯镊子夹取。 </li><li>用于高密度脂蛋白使用适合于特定UHV-STM工具的方法中的STM样品架安装样品块。 <ol><li>如果安装在一个含镍的样品架，切割用钛剪刀钽箔阻隔带（APPX 4毫米乘试样高度）。声处理箔片，每次5分钟，在超纯丙酮，异丙醇，甲醇和去离子水，分别通过部分地覆盖有铝箔和注入烧杯干燥用超纯N 2气荷兰国际集团的N 2喷嘴进入的开口。气体流量，直到所有的液体蒸发。使用镍游离镊子，形式箔围绕结束样品然后夹紧在样品架以分离样品的正面和背面，从样品架。 </li></ol></li><li>安装，等离子体清洗和样品架在氧等离子体去除碳污染后。28 </li></ol></li></ol> 2.特高压样品制备<ol><li>通过负载锁或另一优选UHV-安全的方法引入样品放入超高真空系统，使特高压处理和HDL通常可保持在低于1.3×10 -9毫巴（除了下面步骤2.5.1.1）。 </li><li>德加O / N在650℃，监测温度与高温计。确保该室压力是内的背景的25％。在这里所描述的情况下，典型的背景压力是约4.5×10 -10毫巴。 </li><li>德加钨氢裂化灯丝在1,500℃下进行5分钟。如果可能的话激活钛升华泵。 </li><li>执行样本"闪光"的怪圈。 <ol><li>通过加热到1250℃持续20秒，监测T搭配高温计和使用10℃/秒的加热梯度闪样品。不要超过7×10 -9毫巴的最大压力。凉爽通过去除加热电流在小于5秒。 </li><li>在350℃下进行5分钟休息样品。以允许压力恢复到基线。重复3倍。 </li></ol></li><li>执行样本钝化。 <ol><li>使用高温计来监视温度设定样品温度至350℃。介绍1.3×10 -6毫巴超纯H 2到准备室使用泄漏阀。 <ol><li>把对H 2线非常接近系统中的一个泄漏阀冷阱，以进一步纯化的H 2。 </li><li>如果可能的话，泵系统与高速涡轮泵，而不是一个离子泵。这是为了让离子泵不被世博污染样品sed的高压力和排出的污染物。所述泵被放回正常状态大部分氢已被除去之后与样品仍是热的（350℃）。 </li></ol></li><li>打开钨氢裂化灯丝至1400℃下进行12分钟的温度，然后关闭灯丝和H 2气体流量。凉爽样品至室温。 </li></ol></li></ol> 3.扫描隧道显微镜和光刻<ol><li>样品转移到STM，并把样品和STM针尖进入隧道范围内。使用照相机与拆分比20μm的光斑尺寸更好的功率，利用针尖 - 样品结高分辨率光学图像。偏移校正和调整的光学图像，它代表的不失真再现基准标记。 </li><li>卸下所有的照明，以降低系统热不稳定性。确定的表面质量。 <ol><li>使用传统的STM技术与-2.25 V和200 pA的样本偏差，识别麻木尔的表面上的缺陷。 </li><li>如果表面缺陷均低于可接受的水平，移动到下一个步骤。可接受的最大缺陷水平如下:1％的悬挂键; 3％的Si空缺;的1％的污染物。 </li></ol></li><li>要生产设计的HDL型态，包括实验模式和大（1微米×1微米） 的SERP的识别模式。在SERP图案应与垂直于预期的原子力显微镜快速扫描轴长轴矢量绘制，用15-20纳米的间距。骨折的总体格局基本成形状定义应用HDL条件时，其次是尖的路径。24 </li><li>使用矢量输出来自前一步骤中，执行使用HDL FE模式光刻对于大的地区时，7-9 V样值的偏差，1 nA的电流，和0.2 MC /厘米和AP模式光刻用于需要原子精度边缘的小区域或这些区域24 <ol><li>确定最佳AP模式光刻条件由PErforming HDL具有各种范围从2至4个nA的样品偏压条件范围从3.5至4.5伏，电流和线的剂量为2〜4 MC /厘米。选择产生最窄完全取消钝化线的条件。 </li></ol></li><li>执行STM计量上所需的高密度脂蛋白形成图案的区域通过成像在-2.25 V样值偏差和0.2 nA的隧道电流。 <ol><li> [可选]进行纠错。 STM计量后，比较在STM图像与来自步骤3.5的所需图案去钝化图案。如果任何区域显示悬空键的形成不足，重复光刻周期在这些领域。 </li></ol></li><li>完成STM HDL后，脱离样品尖，移动样品装入锁。 </li><li>宣泄和消除样本。在发泄着超纯N 2，通过与惰性，平的基底如蓝宝石清洁接触它保护样本。29后的表面保护，关闭阀门，以任何泵然后介绍尾气作为QUICKLY越好。从系统中删除样本。 </li></ol> 4.样品运输<ol><li>从负载锁定取出样品。从样品架释放样品，其中包括如果可能的话去除箔片障碍。使用聚四氟乙烯（或Ti）的镊子，将样品转运，保持样品的保护的前侧，试图保持大气暴露至小于10分钟。 </li><li>安装在盖样品和松散组装加压样本转运。冲洗与超纯氩1分钟。 在任何点不要疏散系统，或者可能会发生表面损伤。29最后，用Ar的一个小的正压力（〜50-100毫巴）密封样品转运使得样品保持稳定长达一个月。 </li></ol> 5.原子层沉积<ol><li>确保ALD是在适当的沉积温度（100℃）。慢慢增加，在ALD腔室中的氩气压力，直到大气压已经实现。 </li><li>打开ALD室。 </li><li>用一对聚四氟乙烯镊子抓住上边缘的样本的开放样品转运，并迅速转移到ALD室，然后关闭ALD处理室和清洗用氩气流在&lt;2×10 -1毫巴1小时脱气的压力样本。设置进程执行ALD的80次重复成长无定型氧化钛是2.8nm。 <ol><li>使用未修饰的商用的ALD系统在100-150℃的样品温度下，用四氯化钛（ 四氯化钛）和水（H 2 O）的前体在0.3毫巴和0.8毫巴的压力进行沉积与反应物，用的脉冲时间0.1秒和0.05秒，分别为27 </li><li>以下各气体脉冲，吹扫用Ar反应器，持续60秒，在0.2毫巴，以确保最小的背景沉积由于物理吸附的反应物。在这项工作中的掩模，80次ALD循环中使用在100℃下生长大约2.8纳米的无定型氧化钛。 </li></ol&gt; </li><li>慢慢地发泄ALD室与氩气和开放。重复步骤4.1和4.2的样品运输。 </li></ol> 6.原子力显微镜（AFM） <ol><li>保证按照制造商的协议的原子力显微镜的正确校准。打开样品转运，轻轻用镊子取出样品。 </li><li>从转运除去后，牢固地安装示例成使用机械安装方法的原子力显微镜，例如夹紧系统如果可能的话。聚焦AFM相机到样品上，并定位在样品表面上的基准标记对准针尖到基于在步骤3.2的光学计量的图案。 </li><li>确保AFM设置将显示高度和相位信息，并设置扫描尺寸为20至40微米的宽。搞针尖到样品。 </li><li>在使用最高分辨率的高度和相位信息，扫描，直到定位器模式区域被确定。放大到重新构图祗园和定位在其中的图像所需的区域。 </li><li>使用适当的图像质量和分辨率（通常最高可能）取所需的区域的图像。一旦所有期望区域都被扫描，脱开来自样品的小费。卸载样品。重复步骤4.1和4.2的样品运输。 </li></ol> 7.反应离子蚀刻<ol><li>寒意电容耦合的RIE反应器中，以-110℃，然后将样品加载到其前奏室和抽气至7.5×10 -6毫巴。 <ol><li>稳定的温度下进行3分钟。然后把煤气上的O 2流量在8 SCCM（每分钟标准立方厘米），氩在40 SCCM和SF 6在20 SCCM。 </li><li>使用150W的RF放电击等离子体，然后修改该气流以蚀刻为使用SF 6在52标准立方厘米和O 2在8标准立方厘米1分钟。这些气体有Si的相互作用将蚀刻在约20nm / min的速率。30 </sup&gt; </li><li>泵真空至7.5×10 -6毫巴。排气系统RIE。重复步骤4.1和4.2的样品运输。 </li></ol></li></ol> 8.扫描电子显微术（SEM） <ol><li> SEM样品放置和样品引入到系统中。 <ol><li>将非粘性样品安装到一个方便的位置，以方便安装示例。 </li><li>打开样品转运，轻轻用镊子的边缘抢样品，安全地安装到SEM卡口，然后介绍样品组装成SEM样品取出。 </li><li>发泄和开放的SEM室。牢固安装样品组装的SEM样品台。抽空SEM室。 </li></ol></li><li>定位基准。 <ol><li>把放大倍数最低值。选择加速电压和束流的设置，将提供良好的解决方案。先从最低可接受的设置。上去需要。 </li><li>转电子束上。带给广大区域感兴趣的推荐工作距离和eucentric高度。 </li><li>找到并专注于1.1的基准。调整工作距离是必要的。优化聚焦，亮度和对比度。 </li></ol></li><li>定位和图像模式。 <ol><li>相对于基准，定位基于3.2节和第6的原子力显微镜测量的光学测量为了尽量减少对模式的积碳，用附近的非必要功能，优化对焦模式。一旦优化，移动到图案，并获得平面图图像和测量。 </li><li>如果需要的话，倾斜的样品的3D图像和图案高度的测量。对于其他模式，从8.3根据需要重复。 </li></ol></li><li>进行SEM系统结算例程和卸载样本/秒，规定由SEM制造商。样品固定回转运。 </li><li>重复步骤4.3和4.4的样品运输和储存。此时，样品是健壮和可存放的时间无限期。执行后成像分析，如果有必要的。 </li></ol>

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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atomic-level+study+of+the+robustness+of+the+Si(100)-2&#215;1:H+surface+following+exposure+to+ambient+conditions.">Atomic-level study of the robustness of the Si(100)-2&#215;1:H surface following exposure to ambient conditions.</a> App. Phys. Lett. 78 (7), 886-888 (2001).</li><li>Agostino, R., Flamm, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+etching+of+Si+and+SiO2+in+SF6&#8211;O2+mixtures.">Plasma etching of Si and SiO2 in SF6&#8211;O2 mixtures.</a> J. App. Phys. 52 (1), 162 (1981).</li><li>Longo, R. C., McDonnell, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selectivity+of+metal+oxide+atomic+layer+deposition+on+hydrogen+terminated+and+oxidized+Si(001)-(2&#215;1)+surface.">Selectivity of metal oxide atomic layer deposition on hydrogen terminated and oxidized Si(001)-(2&#215;1) surface.</a> J. Vac. Sci Tech. B. 32 (3), 03D112 (2014).</li><li>Ruess, F. J., Oberbeck, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+etched+registration+markers+to+make+four-terminal+electrical+contacts+to+STM-patterned+nanostructures.">The use of etched registration markers to make four-terminal electrical contacts to STM-patterned nanostructures.</a> Nanotechnology. 16 (10), 2446-2449 (2005).</li><li>Ruess, F. J., Pok, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Realization+of+Atomically+Controlled+Dopant+Devices+in+Silicon.">Realization of Atomically Controlled Dopant Devices in Silicon.</a> Small. 3 (4), 563-567 (2007).</li><li>Li, K., Namboodiri, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+formation+of+atomic+step+morphology+on+micropatterned+Si+(100).">Controlled formation of atomic step morphology on micropatterned Si (100).</a> J. Vac. Sci. Tech. B. 29 (4), 041806 (2011).</li><li>Ballard, J. B., Owen, J. H. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pattern+transfer+of+hydrogen+depassivation+lithography+patterns+into+silicon+with+atomically+traceable+placement+and+size+control.">Pattern transfer of hydrogen depassivation lithography patterns into silicon with atomically traceable placement and size control.</a> Journal of Vacuum Science and Technology B. 32 (4), 041804 (2014).</li><li>Gusev, E. P., Cabral, C., Copel, M., D&#8217;Emic, C., Gribelyuk, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=U+ltrathin+HfO+2+films+grown+on+silicon+by+atomic+layer+deposition+for+advanced+gate+dielectrics+applications.">U ltrathin HfO 2 films grown on silicon by atomic layer deposition for advanced gate dielectrics applications.</a> Microelectronic Engineering. 69, 145-151 (2003).</li></ol>

The authors have nothing to disclose.

上面所描述的纳米结构进行计量要求弥合期间使用其他工具如原子力显微镜和SEM HDL和图案位置的前端定位的能力。与此相反，以具有高分辨率位置编码其它发达构图工具，如电子束光刻，在这里进行的高密度脂蛋白，用一个STM进行而得到很好的控制粗定位，所以额外位置识别的协议被使用， 如图3首先，一个长焦距显微镜定位在超高真空系统从针尖 - 样品的结约20cm外。样品被构图为1...

由于纳米技术变得在各种各样领域，认识结构更重要形成增益重要性，特别是在光刻和电子领域。强调计量的重要性在纳米尺度，特别在低于10纳米尺度，但是应当指出，在仅1纳米的特征尺寸的变化表示的分数变化至少10％。该变型可以具有对器件的性能和材料性质显著影响1,2 - 。4使用合成方法，非常精确地形成单独的特征，例如量子点或其它复杂分子可被制造，2,5,6-但通常缺乏相同精度在功能布局和方向，尽管为了提高大小和位置的控制工作。本文阐述的用于制造纳米结构邻近的原子尺寸精度和特征放置原子精度，以及一种方法在功能布局原子计量。使用扫描隧道显微镜（STM）的诱导氢取消钝化光刻（HDL）的原子精度，以原子精确图案与化学敏感的对比度形成在一个表面上。选择性原子层沉积（ALD），然后施加一个硬质的氧化物材料中的图案化的区域，用反应离子蚀刻（RIE）最终转印图案到散装物料，如在图1示意性示出。与标准相结合的高度精确的HDL过程ALD和RIE处理的结果以灵活的方法，以产生纳米结构上以任意形状和定位的表面。 <img alt="图1" src="/files/ftp_upload/52900/52900fig1.jpg" /> 图1.原发性纳米制造工艺步骤。作为一个例子，一个200纳米×200平方纳米被示出。每个圆圈的箭头表示大气暴露和t的步骤站点之间ransport。特高压后，样品制备，样品是用特高压HDL其次是STM计量（左上）图案。 ALD然后进行，接着用AFM测量（右）。 RIE转成图案的Si（100），其次是SEM计量（左下）。 <a href="https://www.jove.com/files/ftp_upload/52900/52900fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 最精确的光刻迄今为止通常涉及扫描探针技术，具体地基于STM的图案化，其中原子分辨率的图案化和官能化已被证明对于许多应用7以前，原子操纵已生产纳米结构的最终精度通过使用单个原子作为构建块，8 ，9,10，但需要在低温条件，从而纳米结构缺乏长期稳定性。 RT原子操纵通过除去从表面的氢原子已被示出，specificalLY高密度脂蛋白。11,12,13的HDL有望使新的类的基础上，表面处理的对比空间定位电子和其他设备。使用的HDL，而不进一步处理，不同的器件架构是可能的，包括悬挂键合线或逻辑器件。14,15,16除了提供电相反，高密度脂蛋白可引入其中，所述钝化H膜层已被除去的表面上的化学对比，在效果创建用于进一步化学修饰的模板。这种化学修饰已被证明在硅和其它表面，显示出对金属，17绝缘体18，甚至半导体的沉积选择性。16,19这些例子都产生二维结构，因此其它处理步骤，必须使用以产生真正的三三维结构的原子分辨控制由高密度脂蛋白承诺。此前，这需要重复图案，19,20,21退火，22 </suP&gt;或更少的很好的解决方法，如尖为基础的电子束诱导沉积。23 类似于电子束光刻，高密度脂蛋白使用电子的局部的磁通，以暴露抗蚀剂。有几个相似之处存在，如与临场变盘的大小和图案效率进行多模式光刻技术的能力。24然而，高密度脂蛋白的真正动力源于它是如何不同于电子束光刻。首先，抗蚀剂中的HDL是氢原子的单层以便抗蚀剂曝光成为数字过程;抗蚀原子或者是或不存在。25由于氢原子的位置对应于底层的Si（100）晶格HDL的过程可以是一个原子精确的过程，尽管应当注意的是，在本文所述的HDL具有纳米精度反对具有原子完美，因此不是数字在这种情况下。由于在高密度脂蛋白的电子源是本地到表面，STM操作的各种模式促进两者吞吐量的优化以及错误检查。在低于〜4.5 V针尖样的偏见，光刻可以在以原子精度，被称为以原子的精确模式（AP模式）的单个原子水平上进行。与此相反，在偏压以上〜7伏，电子直接从尖端到具有宽线宽并高去钝化效率，这里被称为场发射模式（FE模式）样品发出。 HDL吞吐量然后，可以通过仔细组合这两种模式进行优化，虽然整体的吞吐量保持小相对于电子束光刻用构图高达1微米2 /分钟的可能。当偏置被颠倒，使得样品保持在〜-2.25伏，电子隧道从样品到尖端极低激活操作效率，从而使该表面的原子结构的检查既用于纠错和原子级计量。 在图1中所示的该纳米结构物的制造工艺</strong&gt;的用UHV-HDL的步骤开始时，如上所述。以下的HDL，将样品排放到大气中，在该时间所述图案化的区域变得饱和与水，形成一个薄的（ 即，〜1单层）SiO 2层26中传输后，将样品插入到一ALD室，用于沉积二氧化钛（TiO 2的），其厚度约2-3纳米这里沉积，如通过AFM和XPS 27由于二氧化钛反应取决于表面的水饱和度测量，该方法是可能的，尽管这浸透表面与水的气氛曝光。接着，在该ALD掩模图案转移到散装使用的RIE，使硅为20nm除去样品进行蚀刻，用原子力显微镜和SEM测定的蚀刻深度。为了便于计量步骤，在Si（100）晶片图案化有其目的是特高压制备由长工作距离的光学显微镜，原子力显微镜俯视光学成像后是可见的网格线，和低倍率俯视SEM图像。为了帮助识别纳米级结构，1微米2蛇形图案（ 养老金计划 ）进行构图到样品与位于相对于养老金计划固定位置最偏远的纳米图案。 高密度脂蛋白，选择性ALD，和RIE的这种组合可以是用于纳米结构制造的一个重要的过程，它包括在原子尺度计量作为该过程的一个天然副产品。下面，我们包括涉及制造亚10纳米的纳米结构中的Si（100），使用高密度脂蛋白，选择性ALD，和RIE步骤的详细描述。假定一个是本领域技术人员在这些方法中，但信息将包含有关如何对各种处理进行集成。特别强调将给予由作者，以防止同样的困难经历的那些意想不到的困难，特别是涉及到运输和计量。

<table><tbody><tr><td>Si Wafer</td><td>VA Semiconductor</td><td></td><td>P type (Boron) Si&amp;lt;100&gt; &amp;#177; 2 degrees, 280 mm &amp;#177; 25 mm thick, 0.01-0.02 ohm-cm</td></tr><tr><td>Ta foil</td><td>Alfa Aesar</td><td>335</td><td>0.025&amp;nbsp;mm (0.001&amp;nbsp;in) thick, 99.997% (metals basis)</td></tr><tr><td>Methanol</td><td>Alfa Aesar</td><td>19393</td><td>Semiconductor Grade, 99.9%</td></tr><tr><td>2-Propanol</td><td>Alfa Aesar</td><td>19397</td><td>Semiconductor Grade, 99.5%</td></tr><tr><td>Acetone</td><td>Alfa Aesar</td><td>19392</td><td>Semiconductor Grade, 99.5%</td></tr><tr><td>Argon</td><td>Praxair</td><td></td><td>Ultra high purity (grade 5.0)</td></tr><tr><td>Deionized water</td><td>Millipore</td><td>Milli-Q Water Purification System</td><td>&gt;18 MW resistance water produced on demand.</td></tr><tr><td>TiCl&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma Aldrigh</td><td>254312</td><td>&amp;ge;99.995% trace metals basis</td></tr><tr><td>O&lt;sub&gt;2&lt;/sub&gt;</td><td>Matheson</td><td>G2182101</td><td>Research Grade</td></tr><tr><td>SF&lt;sub&gt;6&lt;/sub&gt;</td><td>Matheson</td><td>G2658922</td><td>Ultra high purity (grade 4.7)</td></tr><tr><td>Blue Medium Tack Roll</td><td>Semiconductor Equipment Corporation</td><td>18074</td><td>Thickness 75 &amp;#956;m / 0.003&amp;rdquo;&amp;nbsp; Length 200 M / 660&amp;rsquo;&amp;nbsp;</td></tr></tbody></table>

atomically traceable nanostructure fabrication

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

在这里所描述的情况下，高密度脂蛋白是使用多模光刻进行。24在FE模式，具有8 V样品偏压，1 Na和0.2 MC /厘米（相当于50毫微米/秒尖端速度）进行，尖端移过的表面平行或垂直于硅晶格，产生激活操作的行。虽然这种线形很尖依赖，在这里的情况下，线的完全去钝化部分约为6纳米宽，具有部分去钝化延伸的线两侧另一个为2nm的尾巴。当高精细图案需要，可以使用4 V样值的偏差，4 nA的，和4 ...

Watch this Scientific Journal Video about Atomically Traceable Nanostructure Fabrication at JoVE.com

Atomically Traceable Nanostructure Fabrication

We report a protocol for combining the atomic metrology of the Scanning Tunneling Microscope for surface patterning with selective Atomic Layer Deposition and Reactive Ion Etching. Using a robust process involving numerous atmospheric exposures and transport, 3D nanostructures with atomic metrology are fabricated.

原子纳米结构可追溯制造

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process ...

atomically-traceable-nanostructure-fabrication

Research

JoVE Journal

Engineering

8.7K 次观看.  Zyvex Labs. We report a protocol for combining the atomic metrology of the Scanning Tunneling Microscope for surface patterning with selective Atomic Layer Deposition and Reactive Ion Etching. Using a robust process involving numerous atmospheric exposures and transport, 3D nanostructures with atomic metrology are fabricated. 

视频: Atomically Traceable Nanostructure Fabrication

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

制备，致密，副本三维碳纳米管微结构成型

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

科研

工程学

Fabricating Nanogaps by Nanoskiving

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two electrodes-and generating them in practical quantities-is still challenging. The preparation of nanogap electrodes using nanoskiving, which is a form of edge lithography, is a fast, simple and powerful technique. This method is an entirely mechanical process which does not include any photo- or electron-beam lithographic steps and does not require any special equipment or infrastructure such as clean rooms. Nanoskiving is used to fabricate electrically addressable nanogaps with control over all three dimensions; the smallest dimension of these structures is defined by the thickness of the sacrificial layer (Al or Ag) or self-assembled monolayers. These wires can be manually positioned by transporting them on drops of water and are directly electrically-addressable; no further lithography is required to connect them to an electrometer.

The fabrication of electrically addressable, high-aspect-ratio (> 1000:1) metal nanowires separated by gaps of single nanometers using either sacrificial layers of aluminum and silver or self-assembled monolayers as templates is described. These nanogap structures are fabricated without a clean room or any photo- or electron-beam lithographic processes by a form of edge lithography known as nanoskiving.

制造由Nanoskiving Nanogaps的

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two ...

化学

A Method to Fabricate Disconnected Silver Nanostructures in 3D

The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.1,2 Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.3-7 However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.8 Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,9 such as coupled metal dot10,11or coupled metal rod12,13 resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses.
In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can form structures in the bulk of a material rather than on its surface.
Most work on 3D direct metal writing has focused on creating self-supported metal structures.14-16 The method described here yields sub-micrometer silver structures that do not need to be self-supported because they are embedded inside a matrix. A doped polymer matrix is prepared using a mixture of silver nitrate (AgNO3), polyvinylpyrrolidone (PVP) and water (H2O). Samples are then patterned by irradiation with an 11-MHz femtosecond laser producing 50-fs pulses. During irradiation, photoreduction of silver ions is induced through nonlinear absorption, creating an aggregate of silver nanoparticles in the focal region. Using this approach we create silver patterns embedded in a doped PVP matrix. Adding 3D translation of the sample extends the patterning to three dimensions.

Femtosecond-laser direct-writing is frequently used to create three-dimensional (3D) patterns in polymers and glasses. However, patterning metals in 3D remains a challenge. We describe a method for fabricating silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm.

一个断开连接的银纳米结构的方法来制作的3D

The standard nanofabrication toolkit includes  techniques primarily aimed at creating 2D patterns in dielectric media. Creating  metal patterns on a ...

Ultrahigh Density Array of Vertically Aligned Small-molecular Organic Nanowires on Arbitrary Substrates

In recent years &pi;-conjugated organic semiconductors have emerged as the active material in a number of diverse applications including large-area, low-cost displays, photovoltaics, printable and flexible electronics and organic spin valves. Organics allow (a) low-cost, low-temperature processing and (b) molecular-level design of electronic, optical and spin transport characteristics. Such features are not readily available for mainstream inorganic semiconductors, which have enabled organics to carve a niche in the silicon-dominated electronics market. The first generation of organic-based devices has focused on thin film geometries, grown by physical vapor deposition or solution processing. However, it has been realized that organic nanostructures can be used to enhance performance of above-mentioned applications and significant effort has been invested in exploring methods for organic nanostructure fabrication.	
A particularly interesting class of organic nanostructures is the one in which vertically oriented organic nanowires, nanorods or nanotubes are organized in a well-regimented, high-density array. Such structures are highly versatile and are ideal morphological architectures for various applications such as chemical sensors, split-dipole nanoantennas, photovoltaic devices with radially heterostructured "core-shell" nanowires, and memory devices with a cross-point geometry. Such architecture is generally realized by a template-directed approach. In the past this method has been used to grow metal and inorganic semiconductor nanowire arrays. More recently &pi;-conjugated polymer nanowires have been grown within nanoporous templates. However, these approaches have had limited success in growing nanowires of technologically important &pi;-conjugated small molecular weight organics, such as tris-8-hydroxyquinoline aluminum (Alq3), rubrene and methanofullerenes, which are commonly used in diverse areas including organic displays, photovoltaics, thin film transistors and spintronics.	
Recently we have been able to address the above-mentioned issue by employing a novel "centrifugation-assisted" approach. This method therefore broadens the spectrum of organic materials that can be patterned in a vertically ordered nanowire array. Due to the technological importance of Alq3, rubrene and methanofullerenes, our method can be used to explore how the nanostructuring of these materials affects the performance of aforementioned organic devices. The purpose of this article is to describe the technical details of the above-mentioned protocol, demonstrate how this process can be extended to grow small-molecular organic nanowires on arbitrary substrates and finally, to discuss the critical steps, limitations, possible modifications, trouble-shooting and future applications.

We report a simple method for fabricating an ultrahigh density array of vertically ordered small-molecular organic nanowires. This method allows for synthesis of complex heterostructured hybrid nanowire geometries, which can be inexpensively grown on arbitrary substrates. These structures have potential applications in organic electronics, optoelectronics, chemical sensing, photovoltaics and spintronics.

超高密度垂直对齐的任意基质的小分子有机纳米线阵列

In  recent years &pi;-conjugated  organic semiconductors have emerged as the active material in a number of  diverse applications including large-area, ...

Writing and Low-Temperature Characterization of Oxide Nanostructures

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions. Oxide interfaces exhibit a wide range of properties that can be controlled include conduction, piezoelectric behavior, ferromagnetism, superconductivity and nonlinear optical properties. Recently, methods for controlling these properties at extreme nanoscale dimensions have been discovered and developed. Here are described explicit step-by-step procedures for creating LaAlO3/SrTiO3 nanostructures using a reversible conductive atomic force microscopy technique. The processing steps for creating electrical contacts to the LaAlO3/SrTiO3 interface are first described. Conductive nanostructures are created by applying voltages to a conductive atomic force microscope tip and locally switching the LaAlO3/SrTiO3 interface to a conductive state. A versatile nanolithography toolkit has been developed expressly for the purpose of controlling the atomic force microscope (AFM) tip path and voltage. Then, these nanostructures are placed in a cryostat and transport measurements are performed. The procedures described here should be useful to others wishing to conduct research in oxide nanoelectronics.

Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

写作和氧化物纳米结构的低温特性

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions.  Oxide ...

Fabrication of Nanopillar-Based Split Ring Resonators for Displacement Current Mediated Resonances in Terahertz Metamaterials

Terahertz (THz) split ring resonator (SRR) metamaterials (MMs) has been studied for gas, chemical, and biomolecular sensing applications because the SRR is not affected by environmental characteristics such as the temperature and pressure surrounding the resonator. Electromagnetic radiation in THz frequencies is biocompatible, which is a critical condition especially for the application of the biomolecular sensing. However, the quality factor (Q-factor) and frequency responses of traditional thin-film based split ring resonator (SRR) MMs are very low, which limits their sensitivities and selectivity as sensors. In this work, novel nanopillar-based SRR MMs, utilizing displacement current, are designed to enhance the Q-factor up to 450, which is around 45 times higher than that of traditional thin-film-based MMs. In addition to the enhanced Q-factor, the nanopillar-based MMs induce a larger frequency shifts (17 times compared to the shift obtained by the traditional thin-film based MMs). Because of the significantly enhanced Q-factors and frequency shifts as well as the property of biocompatible radiation, the THz nanopillar-based SRR are ideal MMs for the development of biomolecular sensors with high sensitivity and selectivity without inducing damage or distortion to biomaterials. A novel fabrication process has been demonstrated to build the nanopillar-based SRRs for displacement current mediated THz MMs. A two-step gold (Au) electroplating process and an atomic layer deposition (ALD) process are used to create sub-10 nm scale gaps between Au nanopillars. Since the ALD process is a conformal coating process, a uniform aluminum oxide (Al2O3) layer with nanometer-scale thickness can be achieved. By sequentially electroplating another Au thin film to fill the spaces between Al2O3 and Au, a close-packed Au-Al2O3-Au structure with nano-scale Al2O3 gaps can be fabricated. The size of the nano-gaps can be well defined by precisely controlling the deposition cycles of the ALD process, which has an accuracy of 0.1 nm.

A protocol for the design and fabrication of a novel nanopillar-based split ring resonator (SRR) is presented.

基于纳米柱裂环谐振器的研制为位移电流共振介导太赫兹超材料

Terahertz (THz) split ring resonator (SRR) metamaterials (MMs) has been studied for gas, chemical, and biomolecular sensing applications because the SRR ...

A Standard and Reliable Method to Fabricate Two-Dimensional Nanoelectronics

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D materials is still in nascent stages, scientists cannot fully rely on traditional semiconductor techniques for related research. Delicate processes from locating the materials to electrode definition need to be well controlled. In this article, a universal fabrication protocol required in manufacturing nanoscale electronics, such as 2D quasi-heterojunction bipolar transistors (Q-HBT), and 2D back-gated transistors are demonstrated. This protocol includes the determination of material position, electron beam lithography (EBL), metal electrode definition, et al. A step by step narrative of the fabrication procedures for these devices are also presented. Furthermore, results show that each of the fabricated devices has achieved high performance with high repeatability. This work reveals a comprehensive description of process flow for preparing 2D nano-electronics, enables the research groups to access this information, and pave the way toward future electronics.

The article aims to introduce a standard and reliable fabrication procedure for the development of future low dimensional nanoelectronics.

制造二维电子学的标准可靠方法

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D ...

Multiscale Structures Aggregated by Imprinted Nanofibers for Functional Surfaces

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing challenge in the field is the fabrication of hybrid micro-nano structures using a facile, cost-effective, and high-throughput method. To overcome these challenges, this paper proposes a protocol to fabricate multiscale structures using only an imprint process with an anodic aluminum oxide (AAO) filter and an evaporative self-aggregation process of nanofibers. Unlike previous attempts that have aimed to straighten nanofibers, we demonstrate a unique fabrication method for multiscale aggregated nanofibers with high aspect ratios. Furthermore, the surface morphology and wettability of these structures on various liquids were investigated to facilitate their use in multifunctional surfaces.

Presented is an easy method to fabricate nano-micro multiscale structures, for functional surfaces, by aggregating nanofibers fabricated using an anodic aluminum oxide filter.

功能表面用印迹纳米纤维聚合的多尺度结构

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing ...

A Label-free Technique for the Spatio-temporal Imaging of Single Cell Secretions

Inter-cellular communication is an integral part of a complex system that helps in maintaining basic cellular activities. As a result, the malfunctioning of such signaling can lead to many disorders. To understand cell-to-cell signaling, it is essential to study the spatial and temporal nature of the secreted molecules from the cell without disturbing the local environment. Various assays have been developed to study protein secretion, however, these methods are typically based on fluorescent probes which disrupt the relevant signaling pathways. To overcome this limitation, a label-free technique is required.
In this paper, we describe the fabrication and application of a label-free localized surface plasmon resonance imaging (LSPRi) technology capable of detecting protein secretions from a single cell. The plasmonic nanostructures are lithographically patterned onto a standard glass coverslip and can be excited using visible light on commercially available light microscopes. Only a small fraction of the coverslip is covered by the nanostructures and hence this technique is well suited for combining common techniques such as fluorescence and bright-field imaging.
A multidisciplinary approach is used in this protocol which incorporates sensor nanofabrication and subsequent biofunctionalization, binding kinetics characterization of ligand and analyte, the integration of the chip and live cells, and the analysis of the measured signal. As a whole, this technology enables a general label-free approach towards mapping cellular secretions and correlating them with the responses of nearby cells.

Inter-cellular communication is critical for controlling various physiological activities within and outside the cell. This paper describes a protocol for measuring the spatio-temporal nature of single cell secretions. To achieve this, a multidisciplinary approach is used which integrates label-free nanoplasmonic sensing with live cell imaging.

无标记技术的单细胞分泌物的时空成像

Inter-cellular communication is an integral part of a complex system that helps in maintaining basic cellular activities. As a result, the malfunctioning ...

生物工程

DNA Origami-Mediated Substrate Nanopatterning of Inorganic Structures for Sensing Applications

Structural DNA nanotechnology provides a viable route for building from the bottom-up using DNA as construction material. The most common DNA nanofabrication technique is called DNA origami, and it allows high-throughput synthesis of accurate and highly versatile structures with nanometer-level precision. Here, it is shown how the spatial information of DNA origami can be transferred to metallic nanostructures by combining the bottom-up DNA origami with the conventionally used top-down lithography approaches. This allows fabrication of billions of tiny nanostructures in one step onto selected substrates. The method is demonstrated using bowtie DNA origami to create metallic bowtie-shaped antenna structures on silicon nitride or sapphire substrates. The method relies on the selective growth of a silicon oxide layer on top of the origami deposition substrate, thus resulting in a patterning mask for following lithographic steps. These nanostructure-equipped surfaces can be further used as molecular sensors (e.g., surface-enhanced Raman spectroscopy (SERS)) and in various other optical applications at the visible wavelength range owing to the small feature sizes (sub-10 nm). The technique can be extended to other materials through methodological modifications; therefore, the resulting optically active surfaces may find use in development of metamaterials and metasurfaces.

Here, we describe a protocol to create discrete and accurate inorganic nanostructures on substrates using DNA origami shapes as guiding templates. The method is demonstrated by creating plasmonic gold bowtie-shaped antennas on a transparent substrate (sapphire).