MoS2 Based TFET: Study on Channel Thickness Dependent Performance

Abstract

The layered two-dimensional (2D) nanoelectronic devices have pulled in colossal consideration due to their magnificent switching features and tremendous on/off current ratios. We have proposed a double gate (DG) Molybdenum Disulfide (MoS2) basedn-type tunnel field effect transistor (TFET) that offers much lower subthreshold swing $(SS)$ compared to conventional MOS devices, which is considered as a supreme figure of merit in transistor performance. Since the channel thickness, that is, the number of MoS2 layer in the channel has a remarkable influence on the device performance; determination of optimum channel thickness (no. of MoS2 layer) is the main focus in the present study. In order to do so, a closed form analytical model for tunneling current and SS are used. In particular, the impact of channel length, screening length, oxide thickness, doping concentration and oxide dielectric strength are studied as a function of channel thickness to optimize the highest band-to-band tunneling (BTBT) current and lowest SS. The results obtained in the present study reveal that the 3.9nm channel thickness (6-layer) based device gives the highest on-current with respect to 0. 65nm/1.95nm(1-layer)/(3-Iayer) based devices, although 0.65nm channel thickness (1-layer) based device shows the lowest SS.