Radio-Frequency Performance of Carbon Nanotube-Based Devices and Circuits Considering Noise and Process Variation

Abstract

This paper provides a global overview of the radiofrequency (RF) performance potential of carbon-nanotube field-effect transistors (CNFET), which for the first time includes the impact of noise. We develop noise and manufacturing process variability extensions for the Stanford CNFET compact model, implemented in Verilog-A and compatible with conventional circuit simulators. CNFET figures-of-merit (FoM) are determined both on the device and on the circuit level. Compared to silicon technology, CNFET devices show much better performance in terms of most of the RF-CMOS requirements of the International Technology Roadmap for Semiconductors. FoM projections for basic RF building blocks (low-noise amplifier and oscillator) show that good performance can already be obtained with simple circuit topologies. The main advantage of CNFET circuits yet lies in easily reaching operation frequencies of several hundreds of gigahertz, which are hard to be exploited by silicon technologies at similar technology nodes.Postprint (published version

Design of Broadband CNFET LNA Based on Extracted I-V Closed-Form Equation

“…Moreover, Fdop and F are doped and intrinsic channel's Fano factor, respectively. According to [19], αH and Fdop are approximately equal to 10 -4 and 0.3 by considering manufacturing results. On the other side, although there is no experimental results for intrinsic short channel shot noise, its theoritical model is widely reported in the litreture [26] in which F is between 0 and 1 for the saturation current and has a reverse relation to ID,L2.…”

“…A qualitative noise analysis on a one channel CNFET based on the Stanford CNFET model is performed in [19]. However, one channel CNFET cannot afford the RF application requirements like current and power demands.…”

“…where gc and gint represent the CNFET_L2 and intrinsic transconductance, respectively. It is accepted that flicker and shot noises are the dominant noise sources in a short channel CNFET [19]. There are three main noise sources in the CNTFET_L2 consisting of the intrinsic channel equivalent noise (shot and flicker noises), and the doped channel drain/source region shot noises ( Fig.7 (a)).…”

“…As well, it is notable that in the Stanford CNFET model, the transistor is considered as a short channel device with the channel length in the range of 10-100 nm in which the transport is quasi-ballistic. Additionally, a qualitative noise analysis is performed in [19] on short channel CNFETs based on the Stanford CNFET model.…”

Variability and reliability analysis of CNFET technology: Impact of manufacturing imperfections

“…In [10] how CNFET manufacturing variations (including CNT diameter and doping variations, the presence of m-CNTs, and the imperfections of m-CNT removal processes) affect the radio frequency performance of CNFET devices and circuits was analyzed. The effects of CNT count variations (CNT density variations + perfect removal of m-CNTs) on CNFET devices and digital circuits were studied in our previous publication [11] and in [12], respectively.…”