Analytical Modeling of Threshold Voltage for Dual-Metal Double-Gate Gate-All-Around (DM-DG-GAA) MOSFET

Abstract

This paper presents, analytical modeling of surface potential,threshold voltage and DIBL for a Dual-Metal Double-Gate Gate-All-Around (DM-DG-GAA) MOSFET considering the parabolic approximation of surface potential. Poisson’s three-dimensional (3D) charge density equation has been solved by using proper boundary conditions to formulate the surface potential throughout the channel length. In this work, two gate metals of distinct work functions are used for gate electrode to create a step profile in channel potential. The potential step profile in surface potential reduces the SCEs in DM-DG-GAA MOSFET. The developed surface potential model is further considered to formulate the threshold voltage (Vth)model by using an effective conductive path and Fermi potential difference. The modeled threshold voltage is further used to find the Drain Induced Barrier Lowering (DIBL) effect. The threshold voltage and the DIBL are discussed with different values of device physical parameters like gate oxide (sio2) thickness, gate length ratio, channel thickness, and screening gate work function. This paper compares the SCEs of DM-DG-GAA MOSFET with Dual-Gate Gate-All-Around (DG-GAA) MOSFET and the results showing that DM-DG-GAA MOSFET offering better short channel characteristics than DG-GAA MOSFET. The model results are verified with simulation results generated from 3D device simulator ATLAS from SILVACO.