A Microfabrication Compatible Method to Fabricate Silicon Nanotubes for Nanoprobe Applications

自上而下的微制造是制造计算机芯片和微机电系统传感芯片的过程，是当前半导体和传感器行业的基础。然而，各种纳米结构和材料的出现可以显著提高这些芯片的性能。 然而，由于其制造工艺与标准微制造工艺的不兼容性，将这些纳米级材料和结构无缝地集成在这些芯片上存在许多挑战。 该奖项支持基础研究，以开发室温微加工工艺来制造硅纳米管。新工艺允许在同一芯片上制造具有其他功能元件或电子器件的硅纳米管，而不会造成热损伤。 纳米管和纳米管使能的功能器件由多种材料如半导体、化合物半导体和金属制成，在医疗保健、生物医学、能源、航空航天和化学工业中具有巨大的应用潜力。因此，这项研究的成果有利于美国经济和社会。这项研究涉及多个学科，包括制造、计算、神经科学和材料科学，从而有助于扩大妇女和代表性不足的少数民族学生对研究的参与，并对工程和科学教育产生积极影响。该项目旨在开发一种可扩展的，环境温度，自上而下的工艺来制造单晶硅纳米管。 硅纳米管的制造是通过简单地使用一系列集成电路（IC）兼容的微细加工工艺来实现的。具体而言，聚苯乙烯纳米球（NS）珠首先自组装成硅晶片上的紧密堆积的单层。然后通过氧等离子体反应离子蚀刻（RIE）来定制这些NS珠以缩小它们的尺寸。利用电感耦合等离子体（ICP）Bosch工艺，以NS珠为掩模制备了硅纳米管。 该研究填补了如何在芯片上实现单个纳米管或纳米管阵列的大规模集成和可控排列的技术知识空白。该研究小组计划进行尖锐的界面相场纳米尺度建模，以便从根本上理解和控制制造坚固硅纳米管的工艺参数的公差范围。此外，研究小组计划开发基于硅纳米管的膜片钳纳米探针，用于神经元和细胞刺激和记录。 具体地，开发了嵌入微尺度细胞培养室内的基于硅纳米管的膜片钳纳米探针阵列，用于记录已分化成少突胶质细胞的成年海马祖细胞培养物中的电生理活性，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响评审标准。

Top-down micromanufacturing is the process for fabricating computer chips and microelectromechanical system sensing chips and is the basis for the current semiconductor and sensor industries. However, the emergence of various nanoscale structures and materials can significantly improve the performance of these chips. However, numerous challenges exist to integrate these nanoscale materials and structures on these chips seamlessly due to incompatibility of their fabrication process with standard microfabrication processes. This award supports fundamental research to develop a room-temperature microfabrication process to fabricate silicon nanotubes. The new process allows the manufacturing of silicon nanotubes with other functional elements or electronics on the same chip without thermal damage. Nanotubes and nanotube-enabled functional devices fabricated from a wide variety of materials such as semiconductors, compound semiconductors, and metals have great potential for applications in healthcare, biomedical, energy, aerospace, and chemical industries. Hence, the outcomes from this research benefits the U.S. economy and society. This research involves several disciplines including manufacturing, computation, neuroscience and material science, thereby helping broaden participation of women and underrepresented minority students in research and having a positive impact on engineering and science education. The project seeks to develop a scalable, ambient temperature, top-down process to fabricate single crystal silicon nanotubes. The fabrication of the silicon nanotubes is realized by simply using a series of integrated circuit (IC)-compatible microfabrication processes. Specifically, polystyrene nanosphere (NS) beads are first self-assembled into a close-packed monolayer on a silicon wafer. These NS beads are then tailored by oxygen plasma reactive ion etching (RIE) to shrink their size. Using the NS beads as the mask, the silicon nanotubes are fabricated by inductively coupled plasma (ICP) Bosch process. This research fills the technical knowledge gap on how to realize the large-scale integration and arrangement of a single nanotube or an array of nanotubes in a controlled manner on a chip. The research team plans to perform sharp interface phase-field nanoscale modeling for fundamental understanding and control of the tolerance range of the processing parameters for fabricating robust silicon nanotubes. In addition, the research team plans to develop silicon nanotube-based patch-clamp nanoprobes for neuronal and cellular stimulation and recordings. Specifically, arrays of silicon nanotube-based patch-clamp nanoprobes embedded within microscale cell culture chambers are developed for recording electrophysiological activity in cultures of adult hippocampal progenitor cells that have differentiated into oligodendrocyte, astrocytes or neurons as well as mapping multiple individual synaptic connections between neurons.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.