Analytical Modeling and Simulation of Subthreshold Characteristics of Recessed-Source/Drain (Re-S/D) Silicon-on-Insulator MOSFETs with Gaussian Doping Profile

This paper presents subthreshold characteristics of recessed source/drain SOI MOSFET having onedimensional (1D) vertical Gaussian doping profile in the channel region. The potential distributions along the channel length direction at the Si–SiO₂ interfaces of Re-S/D SOI MOSFET have been obtained by solving two-dimensional (2D) Poisson's equation. An analytical threshold voltage (V _th) model has been derived by applying a modified threshold voltage condition upon the minimum of Si–SiO₂ interface potential. Further, subthreshold swing (S) and subthreshold current (I _sub) have also been derived considering the diffusion to be the dominant current flow mechanism in the subthreshold regime of device operation. The effects of various device parameters such as channel length (L), channel thickness (t _Si), peak doping concentration (N_p ), project range (R_p ), and straggle (σ _p ) of the Gaussian profile on subthreshold characteristics have been incorporated in developed models. The models' predications are in close agreement with the numerical simulation results obtained from ATLAS device simulator.