Explicit Threshold Voltage Modeling Insight for Short Channel Characterization of a WFE Elliptical GAA Strained-Si MOSFET

Abstract

This paper presents explicit analytical modeling of a gate all around (GAA) strained silicon metal-oxide-semicondutor field-effect transistor (MOSFET) with elliptical cross section by incorporating the popular gate work function engineering (WFE) concept of lateral mole fraction variation from source to drain end. Surface potential and threshold voltage formulation of the proposed structure based on a quasi-three-dimensional scaling equation have been introduced. The derived model is further used to investigate the short channel characteristics of the device in terms of hot carrier effect (HCE), drain-induced barrier lowering (DIBL), threshold voltage roll off (TVRO), and subthreshold slope. The impact of device parameter variation including gate oxide thickness, effective radius, channel doping concentration, germanium (Ge) mole fraction variation in the strained silicon channel along with applied gate to source and drain biases are evaluated on device performance to justify its efficiency in comparison to its single gate material (SM) MOSFET equivalent. Our analytical analysis is further validated by ATLAS-3D device simulated data to verify the precision of the derived model.