Compact Models for High-Frequency Noise in MOSFETs

This project deals with developing a physical understanding of both intrinsic and extrinsic noise mechanisms in a MOSFET. Intrinsic noise mechanisms fundamental to device operation include channel thermal noise, induced gate noise, and induced substrate noise. Extrinsic noise mechanisms present in the MOSFET include the gate resistance noise, substrate resistance noise, substrate current supershot noise and bulk-charge effects and excess channel noise. Consistent with Nyquist's theorem, while the effect of channel thermal noise is observable at zero drain-to-source voltage, all other noise mechanisms cannot manifest themselves under these conditions. However, the attendant fluctuations in the channel charge are observable by the passage of electric current through the device. While most other noise mechanisms have been largely suppressed due to work done by Dr. Jindal at Bell Laboratories in the early 80's, excess channel thermal noise continues to be a challenge. Recent experiments and simulations confirm this excess noise in the sub-100 nm regime. The goal of this project is to better understand the source of this excess noise and develop compact models for the. To better understand the physics this project employs a three-prong approach consisting of measurements, simulations and theoretical analyses.