The effect of the geometry and material properties of a carbon joint produced by electron beam induced deposition on the electrical resistance of a multiwalled carbon nanotube-to-metal contact interface

Abstract

Multiwall carbon nanotubes (MWNTs) are promising candidates for yielding next generation electrical and electronic devices such as interconnects and tips for conductive force microscopy. One of the main challenges in MWNT implementation in such devices is the high contact resistance of the MWNT-metal electrode interface. Electron beam induced deposition (EBID) of an amorphous carbon interface has previously been demonstrated to simultaneously lower the electrical contact resistance and improve the mechanical characteristics of the MWNT-electrode connection. In this work, we investigate the influence of process parameters, such as the electron beam energy, current, geometry, and deposition time, on the EBID-made carbon joint geometry and electrical contact resistance. The influence of the composition of the deposited material on its resistivity is also investigated. The relative importance of each component of the contact resistance and the limiting factor of the overall electrical resistance of a MWNT-based interconnect is determined through a combination of a model analysis and comprehensive experiments.

Enhanced spin accumulation at room temperature in graphene spin valves with amorphous carbon interfacial layers

“…This process is well established 22 and has been used, for example, to fabricate complex carbon structures, 23 conducting bridges, 24 and contacts with carbon nanotubes. 19 Carbon precursors can either be introduced externally using a gas source or simply be present as residual hydrocarbons at the background pressure of a scanning electron microscope (SEM) chamber.…”

“…We use an e-beam area dose of 9000 µC/cm 2 and an accelerating voltage of 30 keV. This dose is about 15-20 times larger than that required to expose PMMA for e-beam lithography, and is large enough to deposit a thin layer of aC at the residual pressure of our system, 19,[22][23][24] which is in the 10 −6 Torr range. For type B devices, we use the same substrate as for type A.…”

Characterization of the Resistance and Force of a Carbon Nanotube/Metal Side Contact by Nanomanipulation

“…The contact length was a visually determined length after we confirmed the CNT was firmly contacted with the Au surface at A2. After bridging the CNT, electron beam was turned off to avoid the irradiation on the electrical contact of CNT/Au interface [33], and three minutes later, we measured the total resistance of the two cantilevers by using the source measure unit. The unit generated a sweep voltage, and a PC recorded the current passing through the CNT.…”

“…After EBID with tungsten deposition, the resistance at A2 can be expressed by x ( n 2 ) · R c 2 . Specifically, x ( n 2 ) · R c 2 is composed of the contact resistances of CNT/Au, Au/W, and W/CNT interfaces and the resistances of W deposits [33]. Despite an increased resistance caused by newly added contact resistances of Au/W and W/CNT interfaces and the resistances of W deposits, W deposition ensures electrical rigid contact benefitting for electron transport.…”

Measurement of MWCNT/Tungsten contact resistance by bridging CNT on two tungsten electrodes with two manipulators

“…However, these techniques have a rather poor control of the contact area between CNT and metal electrode, which is limited to whatever spontaneously forms in the course of an intense heat release at the contact junction. On the contrary, electron beam-induced deposition (EBID) is a technique with high degree of spatial and time-domain control over chemical vapor deposition [13] [14]. Furthermore, it allows to use a variety of materials for making a contact junction [15].…”