A Semiphysical Large-Signal Compact Carbon Nanotube FET Model for Analog RF Applications

Abstract

A compact large-signal model, called Compact Carbon Nanotube Model (CCAM), is presented that accurately describes the shape of DC and small-signal characteristics of fabricated carbon nano-tube FETs (CNTFETs). The new model consists of computationally efficient and smooth current and charge formulations. The model allows, for a given gate length, geometry scaling from single-finger single-tube to multifinger multitube transistors. Ambipolar transport, temperature dependence with self-heating, noise, and a simple trap model have also been included. The new model shows excellent agreement with the data from both the Boltzmann transport equation and measurements of Schottky-barrier CNTFETs and has been implemented in Verilog-A, making it widely available across circuit simulators. IndexTerms-Carbon nanotube field-effect transistor (CNTFET), compact transistor modeling, high-frequency circuit design.

Contact resistance extraction methods for short- and long-channel carbon nanotube field-effect transistors

“…The semiphysical large signal compact model CCAM [18], [19] is used for generating synthetic data to test the different extraction methods. In CCAM, the impact of Schottky barriers is captured by the current source describing the current flow through the channel, while a series contact resistance R C,EC in the equivalent circuit (EC) is added to capture the contribution of the metal-to-CNT interface on the contact resistance.…”

Electrical Characterization of Emerging Transistor Technologies: Issues and Challenges

“…A semi-empirical compact model was developed [15] which includes a simple model for the impact of traps [17] in form of the RC ladder network shown in Fig. 10.…”

“…The trap voltage V tr , which is the difference of the tube potential with and without trapped charges, is determined by the RC ladder network. The trap-free behavior of the multi-tube transistors analyzed here is modeled with the semi-empirical transistor model published in [15]. The trap voltage V tr is incorporated into this model as a threshold voltage shift,…”

“…In section IV, the recently developed compact model CCAM [15] for multi-tube (MT) RF CNTFETs, which features a trap model, is employed to gain some insight into the experimental observations.…”

Analytical Drain Current Model of 1-D Ballistic Schottky-Barrier Transistors

“…It can be applied to quasi-1D SB-FETs based on both nanowires and nanotubes at large bias voltages. The proposed analytical model can replace the transport equations in empirical-based compact models [34], [35] to improve their applicability.…”