Characterization and Modeling of Flicker Noise in Bulk MOSFETs down to Sub-Threshold Regime

In this study, we characterize the flicker noise behavior of bulk planar MOSFETs and propose a model valid down to the sub-threshold region. The model aims to improve the existing BSIM-BULK framework, which is an industry-standard compact model for MOSFETs. The existing model assumes a uniform oxide-trap density (Nt), leading to a constant normalized drain current noise spectral density in the weak inversion region of operation. However, the trap levels may not strictly adhere to the assumption of uniform distribution, leading to a gate bias dependence even in the weak inversion regime. To mitigate this issue, we propose an enhancement to the model by incorporating the non-uniform trap distribution effect, thereby augmenting its overall accuracy. The proposed model is validated against the measurements conducted across a frequency spectrum spanning from 1 Hz to 10 kHz, under various gate and drain bias conditions.