Analysis of Limits of CNTFET Devices through the Design of a Differential Amplifier

In this paper, in order to analyze the limits of CNTFET technology, we study the behavior of a differential amplifier based on CNTFET for application between 50 GHz and 500 GHz, determining the highest gain achievable with low noise level. In particular the examined circuit presents a differential input and single ended output, in which each CNTFET is composed by a single CNT, having the same diameter. The analysis is done without considering embedding parasitic effects since our aim is to study the intrinsic limits of CNTFET technology. We find a solution that is near optimum for gain and noise. In particular we obtain that, using CNTFETs whose channel length is 25 nm, it is possible to reach 27.0 dB gain at 50 GHz and 19.7 dB gain at 500 GHz with a noise spectral power density noise 95 nV/Hz1/2 and 85 nV/Hz1/2 respectively.