Electrical Conductivity of the Aluminum Oxide Diffusion Barrier Following Catalytic Carbon Nanotube Growth

• Main Author: Dodson, Berg Daniel
• Format: Others
• Published: BYU ScholarsArchive 2019
• Subjects: aluminum oxide; carbon nanotubes; diffusion barrier
• Online Access: https://scholarsarchive.byu.edu/etd/7767; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=8767&context=etd

Carbon nanotube templated microfabrication (CNT-M) is a method that allows high-aspect ratio structures to be made for microelectromechanical systems (MEMS) devices. One concern when making monolithic electrical devices using CNT-M is that the aluminum oxide diffusion barrier will create too large of a resistance in the device. However, in developing CNT based MEMS devices, it has been observed that an electrical DC current is capable of transport from a conductive substrate, across the aluminum oxide, and through to the CNT structure grown on top of it. This thesis attempts to determine the mechanisms responsible for current being able to cross the aluminum oxide diffusion barrier easily through sample characterizations. Principally, current-voltage measurements, electron microscopy, XEDS, and SIMS analysis are used to characterize the various samples and determine the process responsible for the observed phenomenon. Through these techniques, it is determined exposure to ethylene gas during the CNT growth recipe used in our lab, regardless of whether CNTs grow on the sample or not, is necessary to cause a drop in resistance across the aluminum oxide, but the that the overall content of iron and carbon in the aluminum oxide do not correlate with this drop in resistance.