Compact Model for L-Shaped Tunnel Field-Effect Transistor Including the 2D Region

Abstract

The L-shaped tunneling field-effect transistor (LTFET) is the only line-tunneling type of TFET to be experimentally demonstrated. To date, there is no literature available on the compact model of LTFET. In this paper, a compact model of LTFET is presented. LTFET has both one-dimensional (1D) and 2D band-to-band tunneling (BTBT) components. The 2D BTBT part dominates in the subthreshold region, whereas the 1D BTBT dominates at higher gate-source biases. The model consists of 1D and 2D BTBT models. The 2D BTBT model is based on the assumption that the electric field originating from the gate and terminating at the source edge is perfectly circular. Tunneling path length is obtained by calculating the distance along an electric field arc that runs from gate to source. The 1D BTBT model is based on a simultaneous solution of the 1D Poisson equation in source and channel regions. Expressions for electric field and potential obtained from integrating the Poisson equation in source and channel regions are solved simultaneously to find the surface potential. Once the surface potential is known, all the other unknown variables, including junction potential and source depletion length, can be calculated. Using the potential profile, tunneling lengths were found for both the source-to-channel BTBT regime, and channel-to-channel BTBT regime. The tunneling lengths were used to calculate the BTBT tunneling rate, and finally, the drain-source current as a function of gate-source, and drain-source bias was calculated. The model results were compared against technology computer-aided design (TCAD) simulation results and were found to be in reasonable agreement for a compact model.

Compact Trap-Assisted-Tunneling Model for Line Tunneling Field-Effect-Transistor Devices

“…This is summarized in Table 1. Details of the 1D and 2D BTBT mechanisms can be found in [15,16]. Depending on the number of traps, their energy level, [12], blue: trap-assisted-tunneling (TAT) current calculated using the trap distribution and method in [13], and red: Band-to-band tunneling (BTBT) current fitted using dynamic nonlocal BTBT current [10].…”

“…This is summarized in Table 1. Details of the 1D and 2D BTBT mechanisms can be found in [15,16]. Depending on the number of traps, their energy level, density and whether the traps are bulk or interface traps, the TAT generated drain current can vary.…”

“…For simplicity, only the 1D potential model is considered [15], and any 2D effects [16] are ignored. The model is divided into two parts.…”

“…The model is divided into two parts. The first part deals with the potential model which has already been reported in detail in [16] and is only briefly described here. Next is the standard Schenk model itself, which has been taken from [10] followed by its compact implementation using the Gaussian distribution function.…”

Compact Model of a Screen under Fan-Induced Swirl Conditions Using a Porous Media Approach

“…The use of compact models to characterize the performance of complex systems in order to make the simulation and design tasks easier and faster is widely extended in different engineering applications: the electric field generated in tunnel field-effect transistors, Najam et al [27]; the circuit models of vertical-cavity surface-emitting lasers, Li et al [28]; the dynamic performance of latent heat thermal storage units, Colangelo et al [29].…”