Compact Model for Low Effective Mass Channel Common Double-Gate MOSFET

Abstract

In the spirit of quantum drift-diffusion formalism, we propose a core compact model for low-effective mass channel common double-gate MOSFET. In contrast to the existing models, carriers in each subband are treated to be in locally thermal equilibrium within that subband, but not with the carriers in a different subband. We observe quasi-linear relationship between energy eigenvalue, quasi-Fermi level, and carrier density in each subband and exploit it to obtain closed-form expressions for drain current and terminal charges. Proposed model, which is free from any unphysical model parameter or interpolating function, captures the essential device physics (strong transverse confinement, wave function penetration, multisubband occupancy, bias-dependent diffusivity, and Fermi–Dirac distribution of the carriers) while preserving the mathematical simplicity of industry standard Silicon MOSFET models. Drain current, conductance, and capacitances calculated from the proposed model are found to be in good agreement with numerical device simulation for a wide range of channel thickness, effective mass, oxide thickness asymmetry, and bias voltages.