RF Performance Potential of Array-Based Carbon-Nanotube Transistors—Part II: Extrinsic Results

Abstract

A comprehensive study, which is presented in two parts, is performed to assess the radio-frequency (RF) performance potential of array-based carbon-nanotube field-effect transistors. In Part II, which is presented in this paper, the infrastructure from Part I is utilized to examine more advanced aspects of the RF characteristics. The subversive effects of the extrinsic (parasitic) resistances and capacitances are added to an array-based structure, and the behaviors of key RF figures of merit, such as the extrinsic unity-current-gain frequency <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> , the attainable power gain, and the unity-power-gain frequency <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> , are examined versus tube pitch and gate-finger layout. The results are compared with those of state-of-the-art high-frequency transistors and to the benchmark determined by the next generation of RF CMOS-as defined by the International Technology Roadmap for Semiconductors for the year 2015-and they provide an indication of the potential advantages and disadvantages of array-based nanotube transistors.