A lossy substrate model for sub-100nm, super-100 GHz f(T) RF CMOS noise extraction and modeling

Abstract

A lossy substrate model is developed to accurately simulate the measured RF noise of 80 nm, super-100 GHz f(T) nMOSFETs. Substrate RLC network built in the model plays a key role responsible for the nonlinear frequency response of noise in 1 similar to 18 GHz regime, which didn't follow the typical thermal noise theory. Good match with the measured S-parameters, Y-parameters, and N-min before de-embedding proves the lossy substrate modell. The intrinsic RF noise can be extracted easily and precisely by the lossy substrate de-embedding using circuit simulation. The accuracy has been justified by good agreement in terms of I-d, g(m), Y-parameters, and fT under wide range of bias conditions and operating frequencies. The extracted intrinsic NFmin as low as 0.6 similar to 0.7dB at 10GHz indicates the advantages of super-100 GHz f(T) offered by the sub-100nm multi-finger nMOS. The frequency dependence of noise resistance R-n suggests the substrate RC coupling induced excess channel thermal noise apparent in 1 similar to 10 GHz regime. The study provides useful guideline for low noise and low power design by using sub-100nm RF CMOS technology.