GOALI: Scaling-up Electronic Purification of Single Wall Carbon Nanotubes via Nanoscale Thermocapillary Flows for High Performance Transistors

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Historically the microelectronics industry has been driving integrated circuit technology development, shrinking silicon transistor sizes, reducing their power consumption and lowering their cost. For strategic electronic applications like satellite technologies, advanced materials development is essential. Single Wall Carbon Nanotubes have emerged as an important material candidate for these applications. The industry believes that electronic devices fabricated using nanotubes may eventually replace silicon-based devices for logic applications; but it is also well known that nanotube-based radiofrequency transistors are important as high-performance analog components in wireless systems. Key to the advance of high performance is the availability of aligned films of semiconducting nanotubes with high purity (>99.999 percent semiconducting nanotubes) at the wafer scale. Scaling-up electronic purification of nanotubes is the key challenge. Recently the Illinois team developed a path to purification for grown aligned nanotubes at levels that meet these daunting requirements. This Grant Opportunity for Academic Liaison with Industry (GOALI) award will support the work needed to scale this purification process to the wafer-scale, and integrate it into the process of record for nanotube field effect transistors in collaboration with Northrup Grumman Corporation. This work will have a great societal benefit, impacting power consumption and performance in wireless technologies, and will serve as one of the first scalable nanomanufacturing development efforts in the area. The work will provide a training platform for future engineers in this new manufacturing paradigm. Moreover this interdisciplinary effort will broaden participation of underrepresented groups in the research through use of the Summer Research Programs at Illinois and Northrup Grumman Corporation. Aligned sub-monolayer films of single walled carbon nanotubes grown by chemical vapor deposition represent a promising materials platform for high-performance electronic applications. However, film electronic purity is a critical issue. Recently the Illinois team developed a path to purification for as-grown aligned materials based on utilization of a thermal resist which serves as an etch barrier for semiconducting nanotubes during processing. The process uses nanoscale thermocapillary flows in thin organic films as a processing strategy for complete, selective removal of metallic nanotubes from aligned arrays of single walled nanotubes. Compatibility with current microelectronics fabrication tools suggests it can serve as a scalable technique for nanotube substrate purification. Microwave excitation leads to efficient, selective removal of metallic tubes via this process, enabling 100 percent purity. The research team will scale-up thermocapillary purification methods for wafer-scale manufacture and will introduce them into the transistor processing workflow at Northrup Grumman. A high volume microwave reactor will be designed, assembled, and developed. Ultimately high-performance, low-power, low noise linear carbon nanotube amplifiers will be fabricated at the wafer-scale.