Study Of Physical Mechanisms And Analytical Models For Charge Plasma-Based Tunneling Field-Effect Transistors

The development of Metal-Oxide-Semiconductor Field-Effect Transistors（MOSFETs）has followed Moore’s Law,with device sizes continuously shrinking and chip integra-tion densities increasing,resulting in a decrease in the device’s threshold voltage(V_th).However,the sub-threshold swing（SS）of MOSFETs at room temperature has a theoret-ical limit of 60m V/dec,which limits further reductions in the threshold voltage.Charge plasma tunneling field-effect transistors（CPTFETs）can overcome the 60m V/dec theoret-ical limit due to their tunneling mechanism and can avoid the problem of manufacturing highly-doped abrupt junctions,which is required for traditional tunneling field-effect tran-sistors（TFETs）,by using electrically doped structures.In this paper,we analyze the phys-ical mechanism of the new CPTFET device and develop analytical models to explain its operation.First,based on the physical mechanism of electrically doped structures,we analyze the influence of metal work function and insulation layer thickness on the potential and equivalent doping concentration distribution of electrically doped structures,and estab-lish an analytical model for the electrically doped effect.Then,using the electrically doped concentration as the boundary condition,we solve the two-dimensional Poisson equation in the channel and establish a two-dimensional band model for CPTFETs.Based on the tunneling distance of carriers determined by the two-dimensional band model,we calculate the electric field strength at the tunneling location and establish a direct cur-rent analytical model for CPTFETs based on the band-to-band tunneling（BTBT）theory.Building on the direct current analytical model,we introduce the modulation of drain volt-age on the surface potential at the center of the one-dimensional channel to derive the analytical expressions for the terminal charges of CPTFETs,which are used to establish the analytical model for the radio frequency electrical characteristics of CPTFETs.We verify the established analytical models using Sentaurus TCAD simulation software and find that the key parameters,including the electrically doped potential distribution,elec-trically doped concentration distribution,band structure in the channel,tunneling current,center potential of the channel,terminal charges,and terminal capacitance,are consistent with simulation results for different geometrical sizes and material parameters.Based on the analytical models and numerical simulations,we analyze and discuss the impact of geometric and material parameters,such as the difference in work function between the active region’s metal electrode and the semiconductor,insulation layer thickness,uncov-ered length,and channel thickness,on the DC electrical characteristics of CPTFETs.We also study the radio frequency electrical characteristics of CPTFETs,focusing on the drain-source capacitance that dominates the operation state and discussing the issues that need to be considered in circuit applications.This paper focuses on the research of the new CPTFET device and proposes an an-alytical model for electrically doped structures from the physical mechanism.Based on this model,we establish a DC and RF electrical characteristic analytical model for CPT-FETs that does not require fitting parameters and has some scalability.This research work can guide device optimization design and circuit simulation,laying a foundation for the application of CPTFETs.