Analytical modeling of Gate All Around (GAA) MOSFET in nanoscale.

Abstract

The nano-scale devices face a major issue i.e. Short Channel Effects, as a result of which the performance of the devices degrade. To enhance the performance of such devices, the SCEs should be reduced. This Thesis contributes to enhance the performance of nano-scaled Quadruple gate MOSFET by reducing the SCEs effects. In this work, an accurate analytical sub threshold models has been developed for an Undoped double gate MOSFET considering parabolic approximation of the channel. The Centre (axial) as well as the surface potential model is obtained by solving the 2-D Poisson’s equation. Using two 2-D double gate MOSFETs and then using perimeter weighted sum method the center potential model of the Quadruple gate MOSFET has been developed. The developed Centre potential model is used further to develop the threshold voltage model. The Centre potential model was further applied to estimate the sub threshold drain current and the sub threshold swing of the device. An extensive analysis of the device parameters like the channel thickness, channel width, oxide thickness, channel length etc. on the sub threshold electrical parameters is demonstrated. This gives a highly accurate model which closely matches with the simulations. The models are verified by the simulations obtained from 3-D numerical device simulator Sentaurus from Synopsys.