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

这一小型企业技术转让(STTR)第一阶段项目的更广泛/商业影响旨在克服无线通信设备用新型半导体商业化所面临的最高风险。随着对无线通信的需求增加(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，在缩小组件占地面积的同时，在数据带宽、能效和功能方面产生必要的提高。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薄的碳层卷成无缝管组成的。碳纳米管的作用就像微小的半导体线，可以显著超过目前的半导体，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，包括高频和线性度，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，使得以前不可能在同一芯片上集成多种类型的高性能电路，从而在更少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，并巩固未来的无线射频技术，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取向技术，克服以前限制纳米管研发的材料和制造挑战。室温对准技术快速、经济实惠且面积可扩展，可实现无缝行业集成。该项目的技术创新将是：(1)开发方法来去除覆盖在纳米管阵列表面和界面上的有机加工残留物，并降低基于纳米管的无线通信晶体管的性能；以及(2)制造和展示基于定向纳米管的无线通信晶体管，该晶体管不受此类杂质的影响。残留物的光谱测量、对杂质敏感的电学测量以及额外的高频晶体管表征将在反馈回路中使用，以通知残留物去除工艺的发展。具体活动将集中在：(1)系统研究不同处理方法选择性清除残留物的效果；(2)确定处理方法如何依赖于阵列密度；以及(3)制造和测试无线通信晶体管。该项目将为治疗库提供杂质去除率的数据库，展示没有残留物造成性能损失的晶体管，以及展示集成在硅上的基于纳米管的晶体管。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.