Modelling of Carbon Nanotube Field Effect Transistors oriented to SPICE software for A/D circuit design

We present a model of Carbon NanoTube Field Effect Transistors (CNTFETs) directly and easily implementable in simulation SPICE software for electronic circuit design. The model is based on analytical approximations and parameters extracted from quantum mechanical simulations of the device and depending on the nanotube diameter and on the oxide capacitance. The comparison of the simulated output and transfer characteristics with those of a numerical model available online and with experimental data shows a relative error less than 5% in both cases. In order to determine the values of CNTFET equivalent circuit elements, a new procedure, based on a best-fitting between the measured and simulated values of output device characteristics, has been proposed. To verify the versatility of the proposed model, we use it in the SPICE simulator to design some A/D electronic circuits, demonstrating the importance of the quantum capacitance dependence on polarization voltages and examining the effects of the CNT quantum resistances.