A Flexibility and Accuracy Comparison Study of Different Current-Voltage Equations for Double-Gate Nano-MOSFET by Simulation and Theory

Abstract

Non-equilibrium Green’s function (NEGF) is a popular method for simulation and modelling of non-equilibrium electron quantum ballistic transport in open mesoscopic system, which is double-gate (DG) nano-MOSFET in this paper, with self-energy scattering effects. In this paper, on-line device simulator nanoMOS using NEGF with finite difference method (FDM) discretization is used to obtain current-voltage (I-V) graph. The simulated on-state current is compared with the calculated and plotted using freeware Scilab code without including NEGF with FDM method to demonstrate the flexibility and accuracy of NEGF with FDM method. Accuracy of 92% is achieved. The difference in due to output resistance at saturation region of I-V curve. Also, this quantum transport model is compared with two others electron transport models derived through Boltzmann statistics along with Einstein relationship, one with high drain bias while other with traditional MOSFET model with ballistic mobility. After analysis, these two approximated equations show 0.87 and 8.8 times, respectively, matches against simulated value. Obviously, nano-MOSFET under high drain bias is closely matched with the quantum model. The traditional MOSFET with ballistic mobility is suitable for very-short-channel length devices (like DG nano-MOSFET) and III-V channel materials with very high-real mobility devices.

Keywords

• conventional model
• current-voltage
• nano-mosfet
• negf
• quantum transport