Modeling of Electrostatics and Drain Current in Nanoscale Double-Gate MOSFETs

Abstract

This work comprises a new technique for 2D compact modeling of short-channel, nanoscale, double-gate MOSFETs. In low-doped devices working in the subthreshold regime, the potential distribution is dominated by the capacitive coupling between the body contacts. This 2D potential is determined by an analytical solution of the Laplace equation for the body using the technique of conformal mapping. Near threshold, where the spatial inversion charge becomes important, a self-consistent solution is applied. In sufficiently strong inversion, the electronic charge will dominate the potential profile in central parts of the channel. For this case, an analytical solution of the 1D Poisson’s equation is used. Based on the modeled barrier topography, the drain current is calculated for the drift-diffusion transport mechanism. The results compare favorably with numerical simulations. A parametrized model for drain current, with all parameters extracted from the modeling framework, is presented as an example of a compact model suitable for inclusion in circuit simulators.