SGER: Fabrication of Innovative Cu/CNT Nanowires

The University Of Central Florida Board Of Trustees, Orlando FL

Investigators

Abstract

CBET-0813741, Chen This Small Grant for Exploratory Research (SGER) project is to develop an innovative Cu/CNT nanowire as potential future interconnects to overcome current technology barriers including electromigration and increased electrical resistivity. The continuous downscaling of line widths has caused two technology barriers associated with Cu interconnects including electromigration and largely increased resistivity. The increased resistivity not only increases the RC delay in the computation but also causes server electromigration as well as Joule heating related reliability concerns. Therefore, it is important to identify solutions to counter increased resistivity associated with nanoscale interconnects. The PI plans to combine copper's large electron density together with carbon nanotube's large mean free path (which is about 750 times greater than that of copper) to achieve potential ultrahigh conductive Cu/CNT nanowires. To do so, he will develop a fabrication process to realize: 1) good interfacial bonding (electrical contact) between CNT and Cu to ensure electron redistribution between CNT and Cu), 2) smooth surface to largely reduce electron-surface scattering. The PI's group has successfully verified that good interfacial bonding between Cu and CNT can be realized by electrochemical deposition in which negatively charged CNTs will attract positively charged Cu ions to form tightly bonded double layers. The PI plans to achieve smooth and uniform Cu coverage on CNT templates with a microchannel reactor by means of a laminar flow and diffusion controlled reaction. The objectives of the research proposal are: 1) to develop a typical microchannel system - a chemical fabrication on chip system for the fabrication of Cu/CNT nanowires; 2) to develop an electrochemical deposition process for the fabrication of Cu/CNT nanowires that Cu will be deposited uniformly onto CNT templates within the microchannel; 3) initiatively investigate fabricated Cu/CNT nanowires, in terms size and morphology (shape and surface condition) as well as electrical conductivity. Intellectual Merit: Cu/CNT nanowire is expected to produce ultrahigh electrical conductivity that is important to counter technology barriers associated with nanoscale interconnects including increased electrical resistivity and electromigration. The ultrahigh conductivity is ensured by the combination of large free electron density (from Cu) and large mean free path (from CNT). Electron redistribution between Cu and CNT will be realized by a tight binding fabrication of electrochemical deposition. Uniform and smooth surface of Cu/CNT nanowires will be fabricated in a microchannel chemical reactor in which lamina flow and diffusion controlled chemical reaction will take place. The success of this SGER project will put PI's group in a good position to compete for larger scale support. Broad Impacts: The success of this proposed research will make significant impacts on nanoscale interconnects as well as on chemical factory on chip (CFOC) for fabrication of nanomaterials. Nanoelectronics will benefit from the success of this work on ultrahigh conductive nanowires (Cu/CNT) and high anti electromigration potentials. These Cu/CNT nanowires are important as building blocks for assembling advanced interconnects for future ICs. In addition, these conductive Cu/CNT nanowires can also be used as advanced electrodes for biological and chemical applications. Educational impacts will be realized through student training and integration of the research with education.