Analog and RF performance analysis of double-gate CNT-FETs with asymmetric source/drain extensions

Abstract This work presents a comprehensive analysis of the analog and radio-frequency (RF) performance of double-gate carbon nanotube field-effect transistors (DG CNT-FETs) employing asymmetric underlap (AUL) engineering. The investigation is carried out using self-consistent atomistic simulations based on the non-equilibrium Green’s function (NEGF) formalism. Initially, the optimal AUL length is determined by evaluating the ON/OFF current ratio ( I ON / I OFF ), a critical metric for digital performance. Subsequently, various analog and RF figures of merit (FoMs) are analyzed, including transconductance ( g m ), output resistance ( r 0 ), intrinsic gain ( g m r 0 ), cut-off frequency ( f T ), transconductance generation factor (TGF), gain frequency product (GFP), and gain transfer frequency product (GTFP). The results indicate that AUL engineering significantly enhances key performance parameters such as I ON / I OFF , r 0 , g m r 0 , GFP, and GTFP. Specifically, an 8 nm AUL leads to a 970% increase in I ON / I OFF , a 70.38% improvement in TGF, a 360% enhancement in intrinsic gain, and notable improvements in GFP (81.44%) and GTFP (150.5%) compared to conventional CNT-FETs. However, f T and TFP are reduced by 77.4% and 36.2%, respectively. These findings highlight critical trade-offs and offer valuable design insights for optimizing CNT-FETs in next-generation analog and RF circuits.