Controlled Growth of Well-Aligned Carbon Nanotubes and Their Assembly

Carbon nanotubes (CNTs) have been proposed for applications in microelectronic applications, especially for electrical interconnects and nanodevices, due to their excellent electrical, thermal and mechanical properties. In order to create interconnect structures comprised of CNT units, it is necessary to control the growth of CNTs in predefined orientations and configurations at a temperature compatible with current microelectronics fabrication process, and the interface with other materials such as metal electrodes. In this paper, we reported a very efficient method to grow well-aligned CNT films/arrays. For aligned CNT array growth, a lift-off process was used to pattern catalyst (Al₂O₃/Fe) islands to diameters of 13 or 20 mum After patterning, chemical vapor deposition (CVD) was invoked to deposit highly aligned CNT arrays using ethylene as the carbon source, and argon and hydrogen as carrier gases. The as-grown CNTs were characterized by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM). To circumvent the high carbon nanotube (CNT) growth temperature and poor adhesion with the substrates that currently plague CNT implementation, we proposed using novel CNT transfer technology, enabled by open-ended CNTs. The process is featured with separation of CNT growth and CNT device assembly. This novel technique shows promising applications for positioning of CNTs on temperature-sensitive substrates, and for the fabrication of field emitters, electrical interconnects, thermal management structures in microelectronics packaging