Reduction of 1/f Noise by Switched Biasing: An Overview

MOSFETs are notorious for having strong low frequency noise (1/f noise or flicker noise). In the late 90's we discovered that this noise can be reduced if you periodically switch the bias on and off. This lead to a STW research project "Reduction of 1/f Noise in MOSFETs by Switched Bias Techniques" (TEL.4756), in which we tried to model the effect of large signal excitation on LF noise and explore its application perspective. This paper gives an overview of the main results obtained during this project. We found that the reduction of LF noise is related to capture and emission of electrons in traps, which renders Random Telegraph Noise (RTS noise). The effect of large signal excitation on LF noise can be modeled by making capture and emission time-constants dependent on the instantaneous bias voltage. We were able to show that the energy distribution of traps in the band-gap determines whether there will be significant noise reduction or not.