Back-gate bias and substrate doping influenced substrate effect in UTBB FD-SOI MOS transistors: analysis and optimization guidelines

Abstract

In this work, we present physical insights into the role of substrate on the anomalous frequency behavior of small-signal trans-conductance and output-conductance in UTBB FDSOI MOS transistors. Using simple DC analysis, we attribute this anomalous behavior to the negative feedback originating from both minority and majority carriers in the substrate at different frequency ranges. Through measurements and detailed TCAD simulations, we have shown that back-gate bias and substrate doping strongly modulate the frequency behavior of trans-conductance and output-conductance. It is finally proposed that circuit/device designers can smartly use the back-gate bias and substrate doping to minimize the Substrate effect and improve the frequency response of device intrinsic gain.