Development of Carbon Nanotubes Vacuum Field Emission Devices
W.P. Kang, Y.M. Wong, J.L. Davidson, D.V. Kerns, J.H. Huang and K.F. Galloway
Vanderbilt University, US
carbon nanotubes, vacuum micro- and nano-electronics, vacuum IC
This report focuses on the design, fabrication and characterization of vacuum field emission (VFE) devices, specifically on the triode and integrated differential amplifier (diff-amp), utilizing CNTs synthesized by microwave plasma chemical vapor deposition in conjunction with semiconductor microfabrication methods. A consistent and reproducible CNTs synthesis method comprised of plasma pretreatment of the catalysts prior to CNT synthesis was developed to tailor the surface profile of vertically aligned CNTs. CNT triode arrays with a well-controlled convex-shaped emitter profile, designed for optimum field emission, were fabricated and their dc and ac performance evaluated. The triodes demonstrated good transistor characteristics with distinct linear, saturation and cutoff regions of operation. The triode amplifier achieved a low gate turn-on of ~16 V, high current density of ~7 A/cm2, high amplification factor of >400, and a projected 50 dB gain at cutoff frequency of ~26 MHz and 20 dB gain at 1 GHz. Lastly, for the first time in vacuum microelectronics, a novel integrated CNT VFE diff-amp was conceptualized and developed by a dual-mask process. The identical pair of integrated amplifiers was well-matched in their device characteristics. Analysis of the measured small-signal characteristics showed a CMRR of ~640 (~56 dB). The successful implementation of the diff-amp demonstrates a new way to achieve temperature and radiation tolerant VFE integrated micro- and nano-electronics.
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Nanotech 2007 Conference Program Abstract