A. Arun

Tunable MEMS capacitors using vertical carbon nanotube arrays grown on metal lines

In this work, tunable MEMS capacitors are realized using a vertically grown carbon nanotube array. The vertical CNT array forms an effective CNT membrane, which can be electrostatically actuated like the conventional metal plates used in MEMS capacitors. The CNT membrane is grown on titanium nitride metal lines, with a Al/Fe bi-layer as buffer layer and catalyst material respectively, using chemical vapor deposition process. Two different anchor configurations are investigated. A maximum capacitance of 400 fF and maximum tunability of 5.8% is extracted from the S-parameter measurements. Using the tunable MEMS vertical array capacitor a voltage controlled oscillator (VCO) is demonstrated showing promise for integrating CNTs for communications applications.

SWNT array resonant gate MOS transistor

We show that thin horizontal arrays of single wall carbon nanotubes (SWNTs) suspended above the channel of silicon MOSFETs can be used as vibrating gate electrodes. This new class of nano-electromechanical system (NEMS) combines the unique mechanical and electronic properties of SWNTs with an integrated silicon-based motion detection. Its electrical response exhibits a clear signature of the mechanical resonance of SWNT arrays (120-150 MHz) showing that these thin horizontal arrays behave as a cohesive, rigid and elastic body membrane with a Youngs modulus in the order of 1-10 GPa and ultra-low mass. The resonant frequency can be tuned by the gate voltage and its dependence is well understood within the continuum mechanics framework.

Micro-Electro-Mechanical capacitors based on vertical carbon nanotube arrays

This paper explores the design and fabrication of Micro-Electro-Mechanical capacitors based on vertical carbon nanotube arrays. The devices are realized in vertically single-clamped parallel plate configurations using a dense array of vertically grown MWCNTs on metal lines. The capacitance tuning is performed by electrostatic actuation. From the pull-in voltage value, based on novel analytical model of single-clamped vertical CNT membranes, we extract an equivalent Young modulus of the CNT array ranging in the 10s of MPa. S-parameter measurements combined with an equivalent circuit model enable the demonstration of a capacitors with values of 50-200fF with a tuning range of the order of 19%.

Tunable Electromechanical resonator based on Carbon Nanotube Array Suspended Gate Field Effect Transistor (CNT-SGFET)

In this paper we report the first experimental demonstration of Micro-Electro-Mechanical resonator based on a Carbon Nanotube-Array-Suspended-Gate-Field-Effect-Transistor (CNT-SGFET). A dense array of single-walled CNT aligned by ac-dielectrophoresis technique forms the suspended gate electrode of a conventional silicon based FET. Resonance frequency of 120 MHz is reported. An equivalent electrical model has been developed for the resonator.

RF NEM capacitive switch based on dense horizontal arrays of CNTs

Carbon nanotubes (CNTs) have been considered one of the most promising material to make nanodevices, in particular nanoelectromechanical systems (NEMS), due to their remarkable mechanical (Youngs modulus ∼1TPa) and electrical (high conductivity for metallic nanotubes) properties, nevertheless their low mass. Several NEMS device categories based on carbon nanotubes have been reported in the literature: sensors [1], non-volatile memories [2], tunable oscillators [3] and nanoswitches [4], which offer high speed at low voltage and power. However, the majority of these works are based on individual tubes, with poor control of the device fabrication, which makes questionable their interest for integrated circuit applications. Hayamizu et al [5] reported the fabrication of nanorelays based on dense arrays of nanotubes, starting from a CNT-wafer. Based on the CNTs array configuration, here we present, for the first time, the fabrication and the characterization of a capacitive shunt NEM switch whose movable electrode is made up of a horizontal CNTs membrane, that could be used for future RF applications.