Optimizing Gate-on-Source Overlapped TFET Device Parameters by Changing Gate Differential Work Function and Overlap Dielectric

Abstract

In this paper, we demonstrate, by using 2-D simulations, that with varying the gate-source overlap dielectric material and differential work function we can boost the maximum cutoff frequency, on/off ratio and the subthreshold swing of DGTFET. We show also that when the main gate dielectric is hafnium dioxide, the best matching source overlap material is silicon dioxide to achieve better performance. The effect of differential work function on all main device parameters is investigated at several source-overlap lengths and at several main gate work functions. For sake of ease of choice of best device performance, we use a relative figure-of-merit for each of the simulated devices and then target the optimization of this figure-of-merit. This approach facilitated the choice of optimum device in a large dataset as we encountered.