RF noise modeling of MOSFETs

Abstract

In this thesis, noise modeling methods of MOSFETs are investigated. The origin of different noise sources for the thermal noise in the conducting channel have been surveyed. Hot-carrier effects and velocity saturation effects are two very important mechanisms which have to be taken into account for the noise modeling of sub-micron transistors. Furthermore, an accurate high-frequency noise modeling for intrinsic transistors relies on an accurate dc and ac model. Therefore, without an accurate dc, ac model, it is impossible to accurately predict the noise performance. Probing pad affects significantly on MOSFETs`` noise performance particularly when width of MOSFETs are small. For accurate analysis on noise parameters of MOSFETs, noise de-embedding procedures are performed previously. And to minimize influence of pad parasitics, we must design pad such that it has smaller parasitics as possible as. The modeling procedure taken in this thesis consists of two directions. One is upward modeling, i.e., based on small signal equivalent circuit component, inner-most noise parameters are calculated. Then noise parameters of MOSFETs are modeled through embedding procedure. The other is downward modeling. Noise parameters of MOSFETs are obtained through de-embedding procedure. Resulting noise parameters of these two procedure are compared to each other, and their validity are conformed. The final results show that resulting noise parameters are different each other considerably. So future works are suggested to complete RF noise modeling issues.