Analytical 3D Approach for Modeling the Electrostatic Potential in Triple-Gate SOI MOSFETs

An analytical approach for modeling the electrostatic potential in nanoscale triple-gate SOI MOS devices is derived. This method uses a 2D solution for the potential within a double-gate FET and takes into account the top gate electrode by applying the conformal mapping technique. In a channel cross-section at the position of the potential barrier an analytical closed-form model for the potential is derived which includes 3D effects. From that solution the subthreshold slope of the device can easily be calculated. The results are in good agreement to numerical device simulations for channel lengths down to 20 nm.