An Efficient and Symbolic Model for Charge Densities in Ballistic Carbon Nanotube FETs

This paper presents a piece-wise linear approximation for modeling charge densities in a Carbon Nanotube FET (CNTFET) in the ballistic regime; this permits a fast and accurate calculation of the charge densities and self-control voltage as well as the source-drain current of the CNTFET. The proposed model is symbolic in terms of CNT features, therefore; it presents a closed-form solution to the self-control voltage in a CNTFET (as a function of parameters such as temperature, device terminal voltages, Fermi levels, and CNT diameter). Results are presented for an evaluation of the model with respect to RMS errors (absolute and normalized). The range for normalized RMS errors are 3%-11% for diameter variations of 3nm-0.5nm, 3%-6% for Fermi level variations of -1.0eV to 0.5eV, and 1%-7% for temperature variations of 100K-500K.