STTR Phase I: Next-Gen Radiofrequency Transistors on Silicon via Aligned, Residue-Free Carbon Nanotubes

这项小型企业技术转让（STTR）第一阶段项目的更广泛/商业影响旨在克服用于无线通信设备的新型半导体商业化所面临的最高风险。随着对无线通信需求的增加（例如，手机、WiFi、物联网设备），无线组件供应商和制造商必须利用新材料和集成方法来提高数据带宽、能源效率和功能，同时缩小组件占地面积。碳纳米管为这个问题提供了一个解决方案。碳纳米管是由一层原子级薄的碳卷成无缝管。碳纳米管的作用就像微小的半导体线，其性能明显优于目前的半导体，如硅和砷化镓。当排列成密集阵列时，纳米管提供了卓越的无线特性，包括高频和线性，这对下一代通信技术至关重要。重要的是，碳纳米管可以沉积在现有的半导体（如硅）上，使以前无法在同一芯片上集成多种类型的高性能电路，允许在更小的空间内实现更多功能。通过解决与无线通信相关的问题，该项目将产生广泛的社会影响，并为未来的无线射频技术奠定基础，同时增强美国在这一重要领域的竞争力。该项目将利用最近开发的碳纳米管对齐技术，克服材料和制造方面的挑战，这些挑战限制了以前的纳米管研究和开发。室温校准技术快速，经济高效，区域可扩展，实现无缝行业集成。该项目的技术创新将是：(1)开发去除纳米管阵列表面和界面上的有机加工残留物的方法，这些残留物会降低纳米管无线通信晶体管的性能；(2)制造并演示基于排列纳米管的无线通信晶体管，这种晶体管不会受到这些杂质的影响。残留物的光谱测量，对杂质敏感的电测量，以及额外的高频晶体管表征将用于反馈回路，以告知残留物去除工艺的发展。具体活动将集中在：(1)系统研究不同处理对选择性去除残留的影响；(2)确定处理对阵列密度的影响；(3)无线通信晶体管的制作与测试。该项目将为处理库提供杂质去除率的数据库，演示不受残留物影响的性能损失的晶体管；以及在硅上集成纳米管晶体管的演示。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The broader/commercial impact of this Small Business Technology Transfer (STTR) Phase I project seeks to overcome the highest risks facing the commercialization of a novel semiconductor for wireless communications devices. As the demand for wireless communication increases (e.g., cell phones, WiFi, Internet of Things devices), wireless component suppliers and manufacturers must utilize new materials and integration methods to yield necessary increases in data bandwidth, energy efficiency, and functionality, while shrinking component footprint. Carbon nanotubes offer a solution to this problem. A carbon nanotube is comprised of an atomically thin layer of carbon rolled into a seamless tube. Carbon nanotubes act like tiny semiconducting wires that can significantly outperform current semiconductors such as silicon and gallium arsenide. When aligned into dense arrays, nanotubes offer superior wireless characteristics including high frequency and linearity, which are vital for next-gen communication technologies. Importantly, carbon nanotubes can be deposited onto existing semiconductors (such as silicon), enabling the previously unfeasible integration of multiple types of high-performance circuits on the same chip, allowing for more functionality in less space. By addressing problems related to wireless communication, this project will have widespread societal impact and underpin the wireless radiofrequency technologies of tomorrow, while bolstering American competitiveness in this important sector.The project will leverage recently developed carbon nanotube alignment technology that overcomes the materials and manufacturing challenges that have limited previous nanotube research and development. The room-temperature alignment technology is fast, cost-effective, and area-scalable – enabling seamless industry integration. The technical innovations of this project will be to: (1) develop approaches to remove organic processing residues that coat the surfaces and interfaces of nanotube arrays and decrease the performance of nanotube-based wireless communications transistors; and (2) fabricate and demonstrate wireless communications transistors based on aligned nanotubes that do not suffer from the effects of such impurities. Spectroscopic measurements of residues, electrical measurements sensitive to impurities, and additional high frequency transistor characterization will be used in a feedback loop to inform residue removal process development. Specific activities will focus on: (1) systematically studying the effect of different treatments to selectively remove residues; (2) determining how the treatments depend on array density; and (3) fabricating and testing wireless communications transistors. The project will provide a database of impurity removal rates for a library of treatments, a demonstration of transistors free of performance loss from residues; and a demonstration of nanotube-based transistors integrated on silicon.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.